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= Internet =
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Introduction
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The Internet (or internet) is the global system of interconnected
computer networks that uses the Internet protocol suite (TCP/IP) to
communicate between networks and devices. It is a 'network of
networks' that consists of private, public, academic, business, and
government networks of local to global scope, linked by a broad array
of electronic, wireless, and optical networking technologies. The
Internet carries a vast range of information resources and services,
such as the inter-linked hypertext documents and applications of the
World Wide Web (WWW), electronic mail, telephony, and file sharing.
The origins of the Internet date back to the development of packet
switching and research commissioned by the United States Department of
Defense in the 1960s to enable time-sharing of computers. The primary
precursor network, the ARPANET, initially served as a backbone for
interconnection of regional academic and military networks in the
1970s. The funding of the National Science Foundation Network as a new
backbone in the 1980s, as well as private funding for other commercial
extensions, led to worldwide participation in the development of new
networking technologies, and the merger of many networks. The linking
of commercial networks and enterprises by the early 1990s marked the
beginning of the transition to the modern Internet, and generated a
sustained exponential growth as generations of institutional,
personal, and mobile computers were connected to the network. Although
the Internet was widely used by academia in the 1980s,
commercialization incorporated its services and technologies into
virtually every aspect of modern life.
Most traditional communication media, including telephony, radio,
television, paper mail and newspapers are reshaped, redefined, or even
bypassed by the Internet, giving birth to new services such as email,
Internet telephony, Internet television, online music, digital
newspapers, and video streaming websites. Newspaper, book, and other
print publishing are adapting to website technology, or are reshaped
into blogging, web feeds and online news aggregators. The Internet has
enabled and accelerated new forms of personal interactions through
instant messaging, Internet forums, and social networking. Online
shopping has grown exponentially for major retailers, small
businesses, and entrepreneurs, as it enables firms to extend their
"brick and mortar" presence to serve a larger market or even sell
goods and services entirely online. Business-to-business and
financial services on the Internet affect supply chains across entire
industries.
The Internet has no single centralized governance in either
technological implementation or policies for access and usage; each
constituent network sets its own policies. The overreaching
definitions of the two principal name spaces in the Internet, the
Internet Protocol address (IP address) space and the Domain Name
System (DNS), are directed by a maintainer organization, the Internet
Corporation for Assigned Names and Numbers (ICANN). The technical
underpinning and standardization of the core protocols is an activity
of the Internet Engineering Task Force (IETF), a non-profit
organization of loosely affiliated international participants that
anyone may associate with by contributing technical expertise. In
November 2006, the Internet was included on 'USA Todays list of 'New
Seven Wonders'.
Terminology
======================================================================
The word 'internetted' was used as early as 1849, meaning
'interconnected' or 'interwoven'. Today, the term 'Internet' most
commonly refers to the global system of interconnected computer
networks, though it may also refer to any group of smaller networks.
When it came into common use, most publications treated the word as a
capitalized proper noun; this has become less common. This reflects
the tendency in English to capitalize new terms and move to lowercase
as they become familiar. It is sometimes still capitalized to
distinguish the global internet from smaller networks, though many
publications, including the 'AP Stylebook', recommend the lowercase
form in every case. In 2016, the 'Oxford English Dictionary' found
that, based on a study of around 2.5 billion printed and online
sources, "Internet" was capitalized in 54% of cases.
The terms 'internet' and 'World Wide Web' are often used
interchangeably; it is common to speak of "'going on the Internet'"
when using a web browser to view web pages. However, the World Wide
Web or 'the Web' is only one of a large number of Internet services, a
collection of documents (web pages) and other web resources, linked by
hyperlinks and URLs.
History
======================================================================
In the 1960s, the Advanced Research Projects Agency (ARPA) of the
United States Department of Defense funded research into time-sharing
of computers. Research into packet switching, one of the fundamental
Internet technologies, started in the work of Paul Baran in the early
1960s and, independently, Donald Davies in 1965. After the Symposium
on Operating Systems Principles in 1967, packet switching from the
proposed NPL network was incorporated into the design for the ARPANET
and other resource sharing networks such as the Merit Network and
CYCLADES, which were developed in the late 1960s and early 1970s.
ARPANET development began with two network nodes which were
interconnected between the Network Measurement Center at the
University of California, Los Angeles (UCLA) Henry Samueli School of
Engineering and Applied Science directed by Leonard Kleinrock, and the
NLS system at SRI International (SRI) by Douglas Engelbart in Menlo
Park, California, on 29 October 1969. The third site was the
Culler-Fried Interactive Mathematics Center at the University of
California, Santa Barbara, followed by the University of Utah Graphics
Department. In a sign of future growth, 15 sites were connected to the
young ARPANET by the end of 1971. These early years were documented in
the 1972 film 'Computer Networks: The Heralds of Resource Sharing'.
Early international collaborations for the ARPANET were rare.
Connections were made in 1973 to the Norwegian Seismic Array (NORSAR)
via a satellite station in Tanum, Sweden, and to Peter Kirstein's
research group at University College London which provided a gateway
to British academic networks. The ARPA projects and international
working groups led to the development of various protocols and
standards by which multiple separate networks could become a single
network or "a network of networks". In 1974, Vint Cerf and Bob Kahn
used the term 'internet' as a shorthand for 'internetwork' in ', and
later RFCs repeated this use. Cerf and Khan credit Louis Pouzin with
important influences on TCP/IP design. Commercial PTT providers were
concerned with developing X.25 public data networks.
Access to the ARPANET was expanded in 1981 when the National Science
Foundation (NSF) funded the Computer Science Network (CSNET). In
1982, the Internet Protocol Suite (TCP/IP) was standardized, which
permitted worldwide proliferation of interconnected networks. TCP/IP
network access expanded again in 1986 when the National Science
Foundation Network (NSFNet) provided access to supercomputer sites in
the United States for researchers, first at speeds of 56 kbit/s and
later at 1.5 Mbit/s and 45 Mbit/s. The NSFNet expanded into academic
and research organizations in Europe, Australia, New Zealand and Japan
in 1988-89. Although other network protocols such as UUCP had global
reach well before this time, this marked the beginning of the Internet
as an intercontinental network. Commercial Internet service providers
(ISPs) emerged in 1989 in the United States and Australia. The ARPANET
was decommissioned in 1990.
Steady advances in semiconductor technology and optical networking
created new economic opportunities for commercial involvement in the
expansion of the network in its core and for delivering services to
the public. In mid-1989, MCI Mail and Compuserve established
connections to the Internet, delivering email and public access
products to the half million users of the Internet. Just months later,
on 1 January 1990, PSInet launched an alternate Internet backbone for
commercial use; one of the networks that added to the core of the
commercial Internet of later years. In March 1990, the first
high-speed T1 (1.5 Mbit/s) link between the NSFNET and Europe was
installed between Cornell University and CERN, allowing much more
robust communications than were capable with satellites. Six months
later Tim Berners-Lee would begin writing WorldWideWeb, the first web
browser after two years of lobbying CERN management. By Christmas
1990, Berners-Lee had built all the tools necessary for a working Web:
the HyperText Transfer Protocol (HTTP) 0.9, the HyperText Markup
Language (HTML), the first Web browser (which was also a HTML editor
and could access Usenet newsgroups and FTP files), the first HTTP
server software (later known as CERN httpd), the first web server, and
the first Web pages that described the project itself. In 1991 the
Commercial Internet eXchange was founded, allowing PSInet to
communicate with the other commercial networks CERFnet and Alternet.
Stanford Federal Credit Union was the first financial institution to
offer online Internet banking services to all of its members in
October 1994. In 1996, OP Financial Group, also a cooperative bank,
became the second online bank in the world and the first in Europe. By
1995, the Internet was fully commercialized in the U.S. when the
NSFNet was decommissioned, removing the last restrictions on use of
the Internet to carry commercial traffic.
As technology advanced and commercial opportunities fueled reciprocal
growth, the volume of Internet traffic started experiencing similar
characteristics as that of the scaling of MOS transistors, exemplified
by Moore's law, doubling every 18 months. This growth, formalized as
Edholm's law, was catalyzed by advances in MOS technology, laser
lightwave systems, and noise performance.
Since 1995, the Internet has tremendously impacted culture and
commerce, including the rise of near instant communication by email,
instant messaging, telephony (Voice over Internet Protocol or VoIP),
two-way interactive video calls, and the World Wide Web with its
discussion forums, blogs, social networking, and online shopping
sites. Increasing amounts of data are transmitted at higher and higher
speeds over fiber optic networks operating at 1-Gbit/s, 10-Gbit/s, or
more. The Internet continues to grow, driven by ever greater amounts
of online information and knowledge, commerce, entertainment and
social networking. During the late 1990s, it was estimated that
traffic on the public Internet grew by 100 percent per year, while the
mean annual growth in the number of Internet users was thought to be
between 20% and 50%. This growth is often attributed to the lack of
central administration, which allows organic growth of the network, as
well as the non-proprietary nature of the Internet protocols, which
encourages vendor interoperability and prevents any one company from
exerting too much control over the network. , the estimated total
number of Internet users was 2.095 billion (30.2% of world
population). It is estimated that in 1993 the Internet carried only 1%
of the information flowing through two-way telecommunication. By 2000
this figure had grown to 51%, and by 2007 more than 97% of all
telecommunicated information was carried over the Internet.
Governance
======================================================================
The Internet is a global network that comprises many voluntarily
interconnected autonomous networks. It operates without a central
governing body. The technical underpinning and standardization of the
core protocols (IPv4 and IPv6) is an activity of the Internet
Engineering Task Force (IETF), a non-profit organization of loosely
affiliated international participants that anyone may associate with
by contributing technical expertise. To maintain interoperability, the
principal name spaces of the Internet are administered by the Internet
Corporation for Assigned Names and Numbers (ICANN). ICANN is governed
by an international board of directors drawn from across the Internet
technical, business, academic, and other non-commercial communities.
ICANN coordinates the assignment of unique identifiers for use on the
Internet, including domain names, Internet Protocol (IP) addresses,
application port numbers in the transport protocols, and many other
parameters. Globally unified name spaces are essential for maintaining
the global reach of the Internet. This role of ICANN distinguishes it
as perhaps the only central coordinating body for the global Internet.
Regional Internet registries (RIRs) were established for five regions
of the world. The African Network Information Center (AfriNIC) for
Africa, the American Registry for Internet Numbers (ARIN) for North
America, the Asia-Pacific Network Information Centre (APNIC) for Asia
and the Pacific region, the Latin American and Caribbean Internet
Addresses Registry (LACNIC) for Latin America and the Caribbean
region, and the Réseaux IP Européens - Network Coordination Centre
(RIPE NCC) for Europe, the Middle East, and Central Asia were
delegated to assign Internet Protocol address blocks and other
Internet parameters to local registries, such as Internet service
providers, from a designated pool of addresses set aside for each
region.
The National Telecommunications and Information Administration, an
agency of the United States Department of Commerce, had final approval
over changes to the DNS root zone until the IANA stewardship
transition on 1 October 2016. The Internet Society (ISOC) was founded
in 1992 with a mission to '"assure the open development, evolution and
use of the Internet for the benefit of all people throughout the
world"'. Its members include individuals (anyone may join) as well as
corporations, organizations, governments, and universities. Among
other activities ISOC provides an administrative home for a number of
less formally organized groups that are involved in developing and
managing the Internet, including: the Internet Engineering Task Force
(IETF), Internet Architecture Board (IAB), Internet Engineering
Steering Group (IESG), Internet Research Task Force (IRTF), and
Internet Research Steering Group (IRSG). On 16 November 2005, the
United Nations-sponsored World Summit on the Information Society in
Tunis established the Internet Governance Forum (IGF) to discuss
Internet-related issues.
Infrastructure
======================================================================
The communications infrastructure of the Internet consists of its
hardware components and a system of software layers that control
various aspects of the architecture. As with any computer network, the
Internet physically consists of routers, media (such as cabling and
radio links), repeaters, modems etc. However, as an example of
internetworking, many of the network nodes are not necessarily
internet equipment per se, the internet packets are carried by other
full-fledged networking protocols with the Internet acting as a
homogeneous networking standard, running across heterogeneous
hardware, with the packets guided to their destinations by IP routers.
Routing and service tiers
===========================
Internet service providers (ISPs) establish the worldwide connectivity
between individual networks at various levels of scope. End-users who
only access the Internet when needed to perform a function or obtain
information, represent the bottom of the routing hierarchy. At the top
of the routing hierarchy are the tier 1 networks, large
telecommunication companies that exchange traffic directly with each
other via very high speed fibre optic cables and governed by peering
agreements. Tier 2 and lower level networks buy Internet transit from
other providers to reach at least some parties on the global Internet,
though they may also engage in peering. An ISP may use a single
upstream provider for connectivity, or implement multihoming to
achieve redundancy and load balancing. Internet exchange points are
major traffic exchanges with physical connections to multiple ISPs.
Large organizations, such as academic institutions, large enterprises,
and governments, may perform the same function as ISPs, engaging in
peering and purchasing transit on behalf of their internal networks.
Research networks tend to interconnect with large subnetworks such as
GEANT, GLORIAD, Internet2, and the UK's national research and
education network, JANET. Both the Internet IP routing structure and
hypertext links of the World Wide Web are examples of scale-free
networks. Computers and routers use routing tables in their operating
system to direct IP packets to the next-hop router or destination.
Routing tables are maintained by manual configuration or automatically
by routing protocols. End-nodes typically use a default route that
points toward an ISP providing transit, while ISP routers use the
Border Gateway Protocol to establish the most efficient routing across
the complex connections of the global Internet.
Access
========
Common methods of Internet access by users include dial-up with a
computer modem via telephone circuits, broadband over coaxial cable,
fiber optics or copper wires, Wi-Fi, satellite, and cellular telephone
technology (e.g. 3G, 4G). The Internet may often be accessed from
computers in libraries and Internet cafes. Internet access points
exist in many public places such as airport halls and coffee shops.
Various terms are used, such as 'public Internet kiosk', 'public
access terminal', and 'Web payphone'. Many hotels also have public
terminals that are usually fee-based. These terminals are widely
accessed for various usages, such as ticket booking, bank deposit, or
online payment. Wi-Fi provides wireless access to the Internet via
local computer networks. Hotspots providing such access include Wi-Fi
cafes, where users need to bring their own wireless devices such as a
laptop or PDA. These services may be free to all, free to customers
only, or fee-based.
Grassroots efforts have led to wireless community networks. Commercial
Wi-Fi services that cover large areas are available in many cities,
such as New York, London, Vienna, Toronto, San Francisco,
Philadelphia, Chicago and Pittsburgh, where the Internet can then be
accessed from places such as a park bench. Experiments have also been
conducted with proprietary mobile wireless networks like Ricochet,
various high-speed data services over cellular networks, and fixed
wireless services. Modern smartphones can also access the Internet
through the cellular carrier network. For Web browsing, these devices
provide applications such as Google Chrome, Safari, and Firefox and a
wide variety of other Internet software may be installed from
app-stores. Internet usage by mobile and tablet devices exceeded
desktop worldwide for the first time in October 2016.
Mobile communication
======================
The International Telecommunication Union (ITU) estimated that, by the
end of 2017, 48% of individual users regularly connect to the
Internet, up from 34% in 2012. Mobile Internet connectivity has played
an important role in expanding access in recent years especially in
Asia and the Pacific and in Africa. The number of unique mobile
cellular subscriptions increased from 3.89 billion in 2012 to 4.83
billion in 2016, two-thirds of the world's population, with more than
half of subscriptions located in Asia and the Pacific. The number of
subscriptions is predicted to rise to 5.69 billion users in 2020. ,
almost 60% of the world's population had access to a 4G broadband
cellular network, up from almost 50% in 2015 and 11% in 2012. The
limits that users face on accessing information via mobile
applications coincide with a broader process of fragmentation of the
Internet. Fragmentation restricts access to media content and tends to
affect poorest users the most.
Zero-rating, the practice of Internet service providers allowing users
free connectivity to access specific content or applications without
cost, has offered opportunities to surmount economic hurdles, but has
also been accused by its critics as creating a two-tiered Internet. To
address the issues with zero-rating, an alternative model has emerged
in the concept of 'equal rating' and is being tested in experiments by
Mozilla and Orange in Africa. Equal rating prevents prioritization of
one type of content and zero-rates all content up to a specified data
cap. A study published by Chatham House, 15 out of 19 countries
researched in Latin America had some kind of hybrid or zero-rated
product offered. Some countries in the region had a handful of plans
to choose from (across all mobile network operators) while others,
such as Colombia, offered as many as 30 pre-paid and 34 post-paid
plans.
A study of eight countries in the Global South found that zero-rated
data plans exist in every country, although there is a great range in
the frequency with which they are offered and actually used in each.
The study looked at the top three to five carriers by market share in
Bangladesh, Colombia, Ghana, India, Kenya, Nigeria, Peru and
Philippines. Across the 181 plans examined, 13 per cent were offering
zero-rated services. Another study, covering Ghana, Kenya, Nigeria and
South Africa, found Facebook's Free Basics and Wikipedia Zero to be
the most commonly zero-rated content.
Internet Protocol Suite
======================================================================
The Internet standards describe a framework known as the Internet
protocol suite (also called TCP/IP, based on the first two
components.) This is a model architecture that divides methods into a
layered system of protocols, originally documented in and .
Layers
========
The software layers correspond to the environment or scope in which
their services operate. At the top is the application layer, space for
the application-specific networking methods used in software
applications. For example, a web browser program uses the
client-server application model and a specific protocol of interaction
between servers and clients, while many file-sharing systems use a
peer-to-peer paradigm.
Below this top layer, the transport layer connects applications on
different hosts with a logical channel through the network with
appropriate data exchange methods. It provides several services
including ordered, reliable delivery (TCP), and an unreliable datagram
service (UDP).
Underlying these layers are the networking technologies that
interconnect networks at their borders and exchange traffic across
them. The Internet layer implements the Internet Protocol which
enables computers to identify and locate each other by Internet
Protocol (IP) addresses, and route their traffic via intermediate
(transit) networks. The internet protocol layer code is independent of
the type of network that it is physically running over.
At the bottom of the architecture is the link layer, which provides
logical connectivity between hosts. The link layer code is usually the
only software part customized to the type of physical networking link
protocol. Many link layers have been implemented and each operates
over a type of network link, such as within a local area network (LAN)
or wide area network (e.g. Wi-Fi or Ethernet or a dial-up connection,
ATM etc.).
Internet protocol
===================
Conceptual data flow in a simple network topology of two hosts ('A'
and 'B') connected by a link between their respective routers. The
application on each host executes read and write operations as if the
processes were directly connected to each other by some kind of data
pipe. After establishment of this pipe, most details of the
communication are hidden from each process, as the underlying
principles of communication are implemented in the lower protocol
layers. In analogy, at the transport layer the communication appears
as host-to-host, without knowledge of the application data structures
and the connecting routers, while at the internetworking layer,
individual network boundaries are traversed at each router.
The most prominent component of the Internet model is the Internet
Protocol (IP). IP enables internetworking and, in essence, establishes
the Internet itself. Two versions of the Internet Protocol exist, IPV4
and IPV6.
IP Addresses
==============
For locating individual computers on the network, the Internet
provides IP addresses. IP addresses are used by the Internet
infrastructure to direct internet packets to their destinations. They
consist of fixed-length numbers, which are found within the packet. IP
addresses are generally assigned to equipment either automatically via
DHCP, or are configured.
However the network also supports other addressing systems. Users
generally enter domain names (e.g. "en.wikipedia.org") instead of IP
addresses because they are easier to remember, they are converted by
the Domain Name System (DNS) into IP addresses which are more
efficient for routing purposes.
IPv4
======
Internet Protocol version 4 (IPv4) defines an IP address as a 32-bit
number. Internet Protocol Version 4 (IPv4) is the initial version used
on the first generation of the Internet and is still in dominant use.
It was designed to address up to ≈4.3 billion (109) hosts. However,
the explosive growth of the Internet has led to IPv4 address
exhaustion, which entered its final stage in 2011, when the global
IPv4 address allocation pool was exhausted.
IPv6
======
Because of the growth of the Internet and the depletion of available
IPv4 addresses, a new version of IP IPv6, was developed in the
mid-1990s, which provides vastly larger addressing capabilities and
more efficient routing of Internet traffic. IPv6 uses 128 bits for the
IP address and was standardized in 1998. IPv6 deployment has been
ongoing since the mid-2000s. IPv6 is currently in growing deployment
around the world, since Internet address registries (RIRs) began to
urge all resource managers to plan rapid adoption and conversion.
IPv6 is not directly interoperable by design with IPv4. In essence, it
establishes a parallel version of the Internet not directly accessible
with IPv4 software. Thus, translation facilities must exist for
internetworking or nodes must have duplicate networking software for
both networks. Essentially all modern computer operating systems
support both versions of the Internet Protocol. Network
infrastructure, however, has been lagging in this development. Aside
from the complex array of physical connections that make up its
infrastructure, the Internet is facilitated by bi- or multi-lateral
commercial contracts, e.g., peering agreements, and by technical
specifications or protocols that describe the exchange of data over
the network. Indeed, the Internet is defined by its interconnections
and routing policies.
Subnetwork
============
A 'subnetwork' or 'subnet' is a logical subdivision of an IP network.
The practice of dividing a network into two or more networks is called
'subnetting'.
Computers that belong to a subnet are addressed with an identical
most-significant bit-group in their IP addresses. This results in the
logical division of an IP address into two fields, the 'network
number' or 'routing prefix' and the 'rest field' or 'host identifier'.
The 'rest field' is an identifier for a specific host or network
interface.
The 'routing prefix' may be expressed in Classless Inter-Domain
Routing (CIDR) notation written as the first address of a network,
followed by a slash character ('/'), and ending with the bit-length of
the prefix. For example, is the prefix of the Internet Protocol
version 4 network starting at the given address, having 24 bits
allocated for the network prefix, and the remaining 8 bits reserved
for host addressing. Addresses in the range to belong to this
network. The IPv6 address specification is a large address block with
296 addresses, having a 32-bit routing prefix.
For IPv4, a network may also be characterized by its 'subnet mask' or
'netmask', which is the bitmask that when applied by a bitwise AND
operation to any IP address in the network, yields the routing prefix.
Subnet masks are also expressed in dot-decimal notation like an
address. For example, is the subnet mask for the prefix .
Traffic is exchanged between subnetworks through routers when the
routing prefixes of the source address and the destination address
differ. A router serves as a logical or physical boundary between the
subnets.
The benefits of subnetting an existing network vary with each
deployment scenario. In the address allocation architecture of the
Internet using CIDR and in large organizations, it is necessary to
allocate address space efficiently. Subnetting may also enhance
routing efficiency, or have advantages in network management when
subnetworks are administratively controlled by different entities in a
larger organization. Subnets may be arranged logically in a
hierarchical architecture, partitioning an organization's network
address space into a tree-like routing structure.
IETF
======
While the hardware components in the Internet infrastructure can often
be used to support other software systems, it is the design and the
standardization process of the software that characterizes the
Internet and provides the foundation for its scalability and success.
The responsibility for the architectural design of the Internet
software systems has been assumed by the Internet Engineering Task
Force (IETF). The IETF conducts standard-setting work groups, open to
any individual, about the various aspects of Internet architecture.
Resulting contributions and standards are published as 'Request for
Comments' (RFC) documents on the IETF web site. The principal methods
of networking that enable the Internet are contained in specially
designated RFCs that constitute the Internet Standards. Other less
rigorous documents are simply informative, experimental, or
historical, or document the best current practices (BCP) when
implementing Internet technologies.
Applications and services
======================================================================
The Internet carries many applications and services, most prominently
the World Wide Web, including social media, electronic mail, mobile
applications, multiplayer online games, Internet telephony, file
sharing, and streaming media services.
Most servers that provide these services are today hosted in data
centers, and content is often accessed through high-performance
content delivery networks.
World Wide Web
================
The World Wide Web is a global collection of documents, images,
multimedia, applications, and other resources, logically interrelated
by hyperlinks and referenced with Uniform Resource Identifiers (URIs),
which provide a global system of named references. URIs symbolically
identify services, web servers, databases, and the documents and
resources that they can provide. Hypertext Transfer Protocol (HTTP) is
the main access protocol of the World Wide Web. Web services also use
HTTP for communication between software systems for information
transfer, sharing and exchanging business data and logistic and is one
of many languages or protocols that can be used for communication on
the Internet.
World Wide Web browser software, such as Microsoft's Internet
Explorer/Edge, Mozilla Firefox, Opera, Apple's Safari, and Google
Chrome, lets users navigate from one web page to another via the
hyperlinks embedded in the documents. These documents may also contain
any combination of computer data, including graphics, sounds, text,
video, multimedia and interactive content that runs while the user is
interacting with the page. Client-side software can include
animations, games, office applications and scientific demonstrations.
Through keyword-driven Internet research using search engines like
Yahoo!, Bing and Google, users worldwide have easy, instant access to
a vast and diverse amount of online information. Compared to printed
media, books, encyclopedias and traditional libraries, the World Wide
Web has enabled the decentralization of information on a large scale.
The Web has enabled individuals and organizations to publish ideas and
information to a potentially large audience online at greatly reduced
expense and time delay. Publishing a web page, a blog, or building a
website involves little initial cost and many cost-free services are
available. However, publishing and maintaining large, professional web
sites with attractive, diverse and up-to-date information is still a
difficult and expensive proposition. Many individuals and some
companies and groups use 'web logs' or blogs, which are largely used
as easily updatable online diaries. Some commercial organizations
encourage staff to communicate advice in their areas of specialization
in the hope that visitors will be impressed by the expert knowledge
and free information, and be attracted to the corporation as a result.
Advertising on popular web pages can be lucrative, and e-commerce,
which is the sale of products and services directly via the Web,
continues to grow. Online advertising is a form of marketing and
advertising which uses the Internet to deliver promotional marketing
messages to consumers. It includes email marketing, search engine
marketing (SEM), social media marketing, many types of display
advertising (including web banner advertising), and mobile
advertising. In 2011, Internet advertising revenues in the United
States surpassed those of cable television and nearly exceeded those
of broadcast television. Many common online advertising practices are
controversial and increasingly subject to regulation.
When the Web developed in the 1990s, a typical web page was stored in
completed form on a web server, formatted in HTML, complete for
transmission to a web browser in response to a request. Over time, the
process of creating and serving web pages has become dynamic, creating
a flexible design, layout, and content. Websites are often created
using content management software with, initially, very little
content. Contributors to these systems, who may be paid staff, members
of an organization or the public, fill underlying databases with
content using editing pages designed for that purpose while casual
visitors view and read this content in HTML form. There may or may not
be editorial, approval and security systems built into the process of
taking newly entered content and making it available to the target
visitors.
Communication
===============
Email is an important communications service available via the
Internet. The concept of sending electronic text messages between
parties, analogous to mailing letters or memos, predates the creation
of the Internet. Pictures, documents, and other files are sent as
email attachments. Email messages can be cc-ed to multiple email
addresses.
Internet telephony is a common communications service realized with
the Internet. The name of the principle internetworking protocol, the
Internet Protocol, lends its name to voice over Internet Protocol
(VoIP). The idea began in the early 1990s with walkie-talkie-like
voice applications for personal computers. VoIP systems now dominate
many markets, and are as easy to use and as convenient as a
traditional telephone. The benefit has been in substantial cost
savings over traditional telephone calls, especially over long
distances. Cable, ADSL, and mobile data networks provide Internet
access in customer premises and inexpensive VoIP network adapters
provide the connection for traditional analog telephone sets. The
voice quality of VoIP often exceeds that of traditional calls.
Remaining problems for VoIP include the situation that emergency
services may not be universally available, and that devices rely on a
local power supply, while older traditional phones are powered from
the local loop, and typically operate during a power failure.
Data transfer
===============
File sharing is an example of transferring large amounts of data
across the Internet. A computer file can be emailed to customers,
colleagues and friends as an attachment. It can be uploaded to a
website or File Transfer Protocol (FTP) server for easy download by
others. It can be put into a "shared location" or onto a file server
for instant use by colleagues. The load of bulk downloads to many
users can be eased by the use of "mirror" servers or peer-to-peer
networks. In any of these cases, access to the file may be controlled
by user authentication, the transit of the file over the Internet may
be obscured by encryption, and money may change hands for access to
the file. The price can be paid by the remote charging of funds from,
for example, a credit card whose details are also passed—usually fully
encrypted—across the Internet. The origin and authenticity of the file
received may be checked by digital signatures or by MD5 or other
message digests. These simple features of the Internet, over a
worldwide basis, are changing the production, sale, and distribution
of anything that can be reduced to a computer file for transmission.
This includes all manner of print publications, software products,
news, music, film, video, photography, graphics and the other arts.
This in turn has caused seismic shifts in each of the existing
industries that previously controlled the production and distribution
of these products.
Streaming media is the real-time delivery of digital media for the
immediate consumption or enjoyment by end users. Many radio and
television broadcasters provide Internet feeds of their live audio and
video productions. They may also allow time-shift viewing or listening
such as Preview, Classic Clips and Listen Again features. These
providers have been joined by a range of pure Internet "broadcasters"
who never had on-air licenses. This means that an Internet-connected
device, such as a computer or something more specific, can be used to
access on-line media in much the same way as was previously possible
only with a television or radio receiver. The range of available types
of content is much wider, from specialized technical webcasts to
on-demand popular multimedia services. Podcasting is a variation on
this theme, where—usually audio—material is downloaded and played back
on a computer or shifted to a portable media player to be listened to
on the move. These techniques using simple equipment allow anybody,
with little censorship or licensing control, to broadcast audio-visual
material worldwide.
Digital media streaming increases the demand for network bandwidth.
For example, standard image quality needs 1 Mbit/s link speed for SD
480p, HD 720p quality requires 2.5 Mbit/s, and the top-of-the-line HDX
quality needs 4.5 Mbit/s for 1080p.
Webcams are a low-cost extension of this phenomenon. While some
webcams can give full-frame-rate video, the picture either is usually
small or updates slowly. Internet users can watch animals around an
African waterhole, ships in the Panama Canal, traffic at a local
roundabout or monitor their own premises, live and in real time. Video
chat rooms and video conferencing are also popular with many uses
being found for personal webcams, with and without two-way sound.
YouTube was founded on 15 February 2005 and is now the leading website
for free streaming video with more than two billion users. It uses an
HTML5 based web player by default to stream and show video files.
Registered users may upload an unlimited amount of video and build
their own personal profile. YouTube claims that its users watch
hundreds of millions, and upload hundreds of thousands of videos
daily.
Social impact
======================================================================
The Internet has enabled new forms of social interaction, activities,
and social associations. This phenomenon has given rise to the
scholarly study of the sociology of the Internet.
Users
=======
From 2000 to 2009, the number of Internet users globally rose from 394
million to 1.858 billion. By 2010, 22 percent of the world's
population had access to computers with 1 billion Google searches
every day, 300 million Internet users reading blogs, and 2 billion
videos viewed daily on YouTube. In 2014 the world's Internet users
surpassed 3 billion or 43.6 percent of world population, but
two-thirds of the users came from richest countries, with 78.0 percent
of Europe countries population using the Internet, followed by 57.4
percent of the Americas. However, by 2018, Asia alone accounted for
51% of all Internet users, with 2.2 billion out of the 4.3 billion
Internet users in the world coming from that region. The number of
China's Internet users surpassed a major milestone in 2018, when the
country's Internet regulatory authority, China Internet Network
Information Centre, announced that China had 802 million Internet
users. By 2019, China was the world's leading country in terms of
Internet users, with more than 800 million users, followed closely by
India, with some 700 million users, with the United States a distant
third with 275 million users. However, in terms of penetration, China
has a 38.4% penetration rate compared to India's 40% and the United
States's 80%. As of 2020, it was estimated that 4.5 billion people use
the Internet.
The prevalent language for communication via the Internet has always
been English. This may be a result of the origin of the Internet, as
well as the language's role as a lingua franca and as a world
language. Early computer systems were limited to the characters in the
American Standard Code for Information Interchange (ASCII), a subset
of the Latin alphabet.
After English (27%), the most requested languages on the World Wide
Web are Chinese (25%), Spanish (8%), Japanese (5%), Portuguese and
German (4% each), Arabic, French and Russian (3% each), and Korean
(2%). By region, 42% of the world's Internet users are based in Asia,
24% in Europe, 14% in North America, 10% in Latin America and the
Caribbean taken together, 6% in Africa, 3% in the Middle East and 1%
in Australia/Oceania. The Internet's technologies have developed
enough in recent years, especially in the use of Unicode, that good
facilities are available for development and communication in the
world's widely used languages. However, some glitches such as
'mojibake' (incorrect display of some languages' characters) still
remain.
In an American study in 2005, the percentage of men using the Internet
was very slightly ahead of the percentage of women, although this
difference reversed in those under 30. Men logged on more often, spent
more time online, and were more likely to be broadband users, whereas
women tended to make more use of opportunities to communicate (such as
email). Men were more likely to use the Internet to pay bills,
participate in auctions, and for recreation such as downloading music
and videos. Men and women were equally likely to use the Internet for
shopping and banking.
More recent studies indicate that in 2008, women significantly
outnumbered men on most social networking sites, such as Facebook and
Myspace, although the ratios varied with age. In addition, women
watched more streaming content, whereas men downloaded more. In terms
of blogs, men were more likely to blog in the first place; among those
who blog, men were more likely to have a professional blog, whereas
women were more likely to have a personal blog.
Splitting by country, in 2012 Iceland, Norway, Sweden, the
Netherlands, and Denmark had the highest Internet penetration by the
number of users, with 93% or more of the population with access.
Several neologisms exist that refer to Internet users: Netizen (as in
"citizen of the net") refers to those actively involved in improving
online communities, the Internet in general or surrounding political
affairs and rights such as free speech, Internaut refers to operators
or technically highly capable users of the Internet, digital citizen
refers to a person using the Internet in order to engage in society,
politics, and government participation.
File:InternetUsersByLanguagePieChart.svg| Internet users by language
File:WebsitesByLanguagePieChart.svg| Website content languages
Usage
=======
The Internet allows greater flexibility in working hours and location,
especially with the spread of unmetered high-speed connections. The
Internet can be accessed almost anywhere by numerous means, including
through mobile Internet devices. Mobile phones, datacards, handheld
game consoles and cellular routers allow users to connect to the
Internet wirelessly. Within the limitations imposed by small screens
and other limited facilities of such pocket-sized devices, the
services of the Internet, including email and the web, may be
available. Service providers may restrict the services offered and
mobile data charges may be significantly higher than other access
methods.
Educational material at all levels from pre-school to post-doctoral is
available from websites. Examples range from CBeebies, through school
and high-school revision guides and virtual universities, to access to
top-end scholarly literature through the likes of Google Scholar. For
distance education, help with homework and other assignments,
self-guided learning, whiling away spare time, or just looking up more
detail on an interesting fact, it has never been easier for people to
access educational information at any level from anywhere. The
Internet in general and the World Wide Web in particular are important
enablers of both formal and informal education. Further, the Internet
allows universities, in particular, researchers from the social and
behavioral sciences, to conduct research remotely via virtual
laboratories, with profound changes in reach and generalizability of
findings as well as in communication between scientists and in the
publication of results.
The low cost and nearly instantaneous sharing of ideas, knowledge, and
skills have made collaborative work dramatically easier, with the help
of collaborative software. Not only can a group cheaply communicate
and share ideas but the wide reach of the Internet allows such groups
more easily to form. An example of this is the free software movement,
which has produced, among other things, Linux, Mozilla Firefox, and
OpenOffice.org (later forked into LibreOffice). Internet chat, whether
using an IRC chat room, an instant messaging system, or a social
networking website, allows colleagues to stay in touch in a very
convenient way while working at their computers during the day.
Messages can be exchanged even more quickly and conveniently than via
email. These systems may allow files to be exchanged, drawings and
images to be shared, or voice and video contact between team members.
Content management systems allow collaborating teams to work on shared
sets of documents simultaneously without accidentally destroying each
other's work. Business and project teams can share calendars as well
as documents and other information. Such collaboration occurs in a
wide variety of areas including scientific research, software
development, conference planning, political activism and creative
writing. Social and political collaboration is also becoming more
widespread as both Internet access and computer literacy spread.
The Internet allows computer users to remotely access other computers
and information stores easily from any access point. Access may be
with computer security, i.e. authentication and encryption
technologies, depending on the requirements. This is encouraging new
ways of working from home, collaboration and information sharing in
many industries. An accountant sitting at home can audit the books of
a company based in another country, on a server situated in a third
country that is remotely maintained by IT specialists in a fourth.
These accounts could have been created by home-working bookkeepers, in
other remote locations, based on information emailed to them from
offices all over the world. Some of these things were possible before
the widespread use of the Internet, but the cost of private leased
lines would have made many of them infeasible in practice. An office
worker away from their desk, perhaps on the other side of the world on
a business trip or a holiday, can access their emails, access their
data using cloud computing, or open a remote desktop session into
their office PC using a secure virtual private network (VPN)
connection on the Internet. This can give the worker complete access
to all of their normal files and data, including email and other
applications, while away from the office. It has been referred to
among system administrators as the Virtual Private Nightmare, because
it extends the secure perimeter of a corporate network into remote
locations and its employees' homes.
Social networking and entertainment
=====================================
Many people use the World Wide Web to access news, weather and sports
reports, to plan and book vacations and to pursue their personal
interests. People use chat, messaging and email to make and stay in
touch with friends worldwide, sometimes in the same way as some
previously had pen pals. Social networking websites such as Facebook,
Twitter, and Myspace have created new ways to socialize and interact.
Users of these sites are able to add a wide variety of information to
pages, to pursue common interests, and to connect with others. It is
also possible to find existing acquaintances, to allow communication
among existing groups of people. Sites like LinkedIn foster commercial
and business connections. YouTube and Flickr specialize in users'
videos and photographs. While social networking sites were initially
for individuals only, today they are widely used by businesses and
other organizations to promote their brands, to market to their
customers and to encourage posts to "go viral". "Black hat" social
media techniques are also employed by some organizations, such as spam
accounts and astroturfing.
A risk for both individuals and organizations writing posts
(especially public posts) on social networking websites, is that
especially foolish or controversial posts occasionally lead to an
unexpected and possibly large-scale backlash on social media from
other Internet users. This is also a risk in relation to controversial
'offline' behavior, if it is widely made known. The nature of this
backlash can range widely from counter-arguments and public mockery,
through insults and hate speech, to, in extreme cases, rape and death
threats. The online disinhibition effect describes the tendency of
many individuals to behave more stridently or offensively online than
they would in person. A significant number of feminist women have been
the target of various forms of harassment in response to posts they
have made on social media, and Twitter in particular has been
criticised in the past for not doing enough to aid victims of online
abuse.
For organizations, such a backlash can cause overall brand damage,
especially if reported by the media. However, this is not always the
case, as any brand damage in the eyes of people with an opposing
opinion to that presented by the organization could sometimes be
outweighed by strengthening the brand in the eyes of others.
Furthermore, if an organization or individual gives in to demands that
others perceive as wrong-headed, that can then provoke a
counter-backlash.
Some websites, such as Reddit, have rules forbidding the posting of
personal information of individuals (also known as doxxing), due to
concerns about such postings leading to mobs of large numbers of
Internet users directing harassment at the specific individuals
thereby identified. In particular, the Reddit rule forbidding the
posting of personal information is widely understood to imply that all
identifying photos and names must be censored in Facebook screenshots
posted to Reddit. However, the interpretation of this rule in relation
to public Twitter posts is less clear, and in any case, like-minded
people online have many other ways they can use to direct each other's
attention to public social media posts they disagree with.
Children also face dangers online such as cyberbullying and approaches
by sexual predators, who sometimes pose as children themselves.
Children may also encounter material which they may find upsetting, or
material which their parents consider to be not age-appropriate. Due
to naivety, they may also post personal information about themselves
online, which could put them or their families at risk unless warned
not to do so. Many parents choose to enable Internet filtering, and/or
supervise their children's online activities, in an attempt to protect
their children from inappropriate material on the Internet. The most
popular social networking websites, such as Facebook and Twitter,
commonly forbid users under the age of 13. However, these policies are
typically trivial to circumvent by registering an account with a false
birth date, and a significant number of children aged under 13 join
such sites anyway. Social networking sites for younger children, which
claim to provide better levels of protection for children, also exist.
The Internet has been a major outlet for leisure activity since its
inception, with entertaining social experiments such as MUDs and MOOs
being conducted on university servers, and humor-related Usenet groups
receiving much traffic. Many Internet forums have sections devoted to
games and funny videos. The Internet pornography and online gambling
industries have taken advantage of the World Wide Web. Although many
governments have attempted to restrict both industries' use of the
Internet, in general, this has failed to stop their widespread
popularity.
Another area of leisure activity on the Internet is multiplayer
gaming. This form of recreation creates communities, where people of
all ages and origins enjoy the fast-paced world of multiplayer games.
These range from MMORPG to first-person shooters, from role-playing
video games to online gambling. While online gaming has been around
since the 1970s, modern modes of online gaming began with subscription
services such as GameSpy and MPlayer. Non-subscribers were limited to
certain types of game play or certain games. Many people use the
Internet to access and download music, movies and other works for
their enjoyment and relaxation. Free and fee-based services exist for
all of these activities, using centralized servers and distributed
peer-to-peer technologies. Some of these sources exercise more care
with respect to the original artists' copyrights than others.
Internet usage has been correlated to users' loneliness. Lonely people
tend to use the Internet as an outlet for their feelings and to share
their stories with others, such as in the "I am lonely will anyone
speak to me" thread.
A 2017 book claimed that the Internet consolidates most aspects of
human endeavor into singular arenas of which all of humanity are
potential members and competitors, with fundamentally negative impacts
on mental health as a result. While successes in each field of
activity are pervasively visible and trumpeted, they are reserved for
an extremely thin sliver of the world's most exceptional, leaving
everyone else behind. Whereas, before the Internet, expectations of
success in any field were supported by reasonable probabilities of
achievement at the village, suburb, city or even state level, the same
expectations in the Internet world are virtually certain to bring
disappointment today: there is always someone else, somewhere on the
planet, who can do better and take the now one-and-only top spot.
Cybersectarianism is a new organizational form which involves: "highly
dispersed small groups of practitioners that may remain largely
anonymous within the larger social context and operate in relative
secrecy, while still linked remotely to a larger network of believers
who share a set of practices and texts, and often a common devotion to
a particular leader. Overseas supporters provide funding and support;
domestic practitioners distribute tracts, participate in acts of
resistance, and share information on the internal situation with
outsiders. Collectively, members and practitioners of such sects
construct viable virtual communities of faith, exchanging personal
testimonies and engaging in the collective study via email, on-line
chat rooms, and web-based message boards." In particular, the British
government has raised concerns about the prospect of young British
Muslims being indoctrinated into Islamic extremism by material on the
Internet, being persuaded to join terrorist groups such as the
so-called "Islamic State", and then potentially committing acts of
terrorism on returning to Britain after fighting in Syria or Iraq.
Cyberslacking can become a drain on corporate resources; the average
UK employee spent 57 minutes a day surfing the Web while at work,
according to a 2003 study by Peninsula Business Services. Internet
addiction disorder is excessive computer use that interferes with
daily life. Nicholas G. Carr believes that Internet use has other
effects on individuals, for instance improving skills of scan-reading
and interfering with the deep thinking that leads to true creativity.
Electronic business
=====================
Electronic business ('e-business') encompasses business processes
spanning the entire value chain: purchasing, supply chain management,
marketing, sales, customer service, and business relationship.
E-commerce seeks to add revenue streams using the Internet to build
and enhance relationships with clients and partners. According to
International Data Corporation, the size of worldwide e-commerce, when
global business-to-business and -consumer transactions are combined,
equate to $16 trillion for 2013. A report by Oxford Economics added
those two together to estimate the total size of the digital economy
at $20.4 trillion, equivalent to roughly 13.8% of global sales.
While much has been written of the economic advantages of
Internet-enabled commerce, there is also evidence that some aspects of
the Internet such as maps and location-aware services may serve to
reinforce economic inequality and the digital divide. Electronic
commerce may be responsible for consolidation and the decline of
mom-and-pop, brick and mortar businesses resulting in increases in
income inequality.
Author Andrew Keen, a long-time critic of the social transformations
caused by the Internet, has focused on the economic effects of
consolidation from Internet businesses. Keen cites a 2013 Institute
for Local Self-Reliance report saying brick-and-mortar retailers
employ 47 people for every $10 million in sales while Amazon employs
only 14. Similarly, the 700-employee room rental start-up Airbnb was
valued at $10 billion in 2014, about half as much as Hilton Worldwide,
which employs 152,000 people. At that time, Uber employed 1,000
full-time employees and was valued at $18.2 billion, about the same
valuation as Avis Rent a Car and The Hertz Corporation combined, which
together employed almost 60,000 people.
Telecommuting
===============
Telecommuting is the performance within a traditional worker and
employer relationship when it is facilitated by tools such as
groupware, virtual private networks, conference calling,
videoconferencing, and voice over IP (VOIP) so that work may be
performed from any location, most conveniently the worker's home. It
can be efficient and useful for companies as it allows workers to
communicate over long distances, saving significant amounts of travel
time and cost. As broadband Internet connections become commonplace,
more workers have adequate bandwidth at home to use these tools to
link their home to their corporate intranet and internal communication
networks.
Collaborative publishing
==========================
Wikis have also been used in the academic community for sharing and
dissemination of information across institutional and international
boundaries. In those settings, they have been found useful for
collaboration on grant writing, strategic planning, departmental
documentation, and committee work. The United States Patent and
Trademark Office uses a wiki to allow the public to collaborate on
finding prior art relevant to examination of pending patent
applications. Queens, New York has used a wiki to allow citizens to
collaborate on the design and planning of a local park. The English
Wikipedia has the largest user base among wikis on the World Wide Web
and ranks in the top 10 among all Web sites in terms of traffic.
Politics and political revolutions
====================================
The Internet has achieved new relevance as a political tool. The
presidential campaign of Howard Dean in 2004 in the United States was
notable for its success in soliciting donation via the Internet. Many
political groups use the Internet to achieve a new method of
organizing for carrying out their mission, having given rise to
Internet activism, most notably practiced by rebels in the Arab
Spring. 'The New York Times' suggested that social media websites,
such as Facebook and Twitter, helped people organize the political
revolutions in Egypt, by helping activists organize protests,
communicate grievances, and disseminate information.
Many have understood the Internet as an extension of the Habermasian
notion of the 'public sphere', observing how network communication
technologies provide something like a global civic forum. However,
incidents of politically motivated Internet censorship have now been
recorded in many countries, including western democracies.
Philanthropy
==============
The spread of low-cost Internet access in developing countries has
opened up new possibilities for peer-to-peer charities, which allow
individuals to contribute small amounts to charitable projects for
other individuals. Websites, such as DonorsChoose and GlobalGiving,
allow small-scale donors to direct funds to individual projects of
their choice. A popular twist on Internet-based philanthropy is the
use of peer-to-peer lending for charitable purposes. Kiva pioneered
this concept in 2005, offering the first web-based service to publish
individual loan profiles for funding. Kiva raises funds for local
intermediary microfinance organizations which post stories and updates
on behalf of the borrowers. Lenders can contribute as little as $25 to
loans of their choice, and receive their money back as borrowers
repay. Kiva falls short of being a pure peer-to-peer charity, in that
loans are disbursed before being funded by lenders and borrowers do
not communicate with lenders themselves.
Security
======================================================================
Internet resources, hardware, and software components are the target
of criminal or malicious attempts to gain unauthorized control to
cause interruptions, commit fraud, engage in blackmail or access
private information.
Malware
=========
Malware is malicious software used and distributed via the Internet.
It includes computer viruses which are copied with the help of humans,
computer worms which copy themselves automatically, software for
denial of service attacks, ransomware, botnets, and spyware that
reports on the activity and typing of users. Usually, these activities
constitute cybercrime. Defense theorists have also speculated about
the possibilities of hackers using cyber warfare using similar methods
on a large scale.
Surveillance
==============
The vast majority of computer surveillance involves the monitoring of
data and traffic on the Internet. In the United States for example,
under the Communications Assistance For Law Enforcement Act, all phone
calls and broadband Internet traffic (emails, web traffic, instant
messaging, etc.) are required to be available for unimpeded real-time
monitoring by Federal law enforcement agencies. Packet capture is the
monitoring of data traffic on a computer network. Computers
communicate over the Internet by breaking up messages (emails, images,
videos, web pages, files, etc.) into small chunks called "packets",
which are routed through a network of computers, until they reach
their destination, where they are assembled back into a complete
"message" again. Packet Capture Appliance intercepts these packets as
they are traveling through the network, in order to examine their
contents using other programs. A packet capture is an information
'gathering' tool, but not an 'analysis' tool. That is it gathers
"messages" but it does not analyze them and figure out what they mean.
Other programs are needed to perform traffic analysis and sift through
intercepted data looking for important/useful information. Under the
Communications Assistance For Law Enforcement Act all U.S.
telecommunications providers are required to install packet sniffing
technology to allow Federal law enforcement and intelligence agencies
to intercept all of their customers' broadband Internet and voice over
Internet protocol (VoIP) traffic.
The large amount of data gathered from packet capturing requires
surveillance software that filters and reports relevant information,
such as the use of certain words or phrases, the access of certain
types of web sites, or communicating via email or chat with certain
parties. Agencies, such as the Information Awareness Office, NSA, GCHQ
and the FBI, spend billions of dollars per year to develop, purchase,
implement, and operate systems for interception and analysis of data.
Similar systems are operated by Iranian secret police to identify and
suppress dissidents. The required hardware and software was allegedly
installed by German Siemens AG and Finnish Nokia.
Censorship
============
Some governments, such as those of Burma, Iran, North Korea, Mainland
China, Saudi Arabia and the United Arab Emirates, restrict access to
content on the Internet within their territories, especially to
political and religious content, with domain name and keyword filters.
In Norway, Denmark, Finland, and Sweden, major Internet service
providers have voluntarily agreed to restrict access to sites listed
by authorities. While this list of forbidden resources is supposed to
contain only known child pornography sites, the content of the list is
secret. Many countries, including the United States, have enacted laws
against the possession or distribution of certain material, such as
child pornography, via the Internet, but do not mandate filter
software. Many free or commercially available software programs,
called content-control software are available to users to block
offensive websites on individual computers or networks, in order to
limit access by children to pornographic material or depiction of
violence.
Performance
======================================================================
As the Internet is a heterogeneous network, the physical
characteristics, including for example the data transfer rates of
connections, vary widely. It exhibits emergent phenomena that depend
on its large-scale organization.
Traffic volume
================
The volume of Internet traffic is difficult to measure, because no
single point of measurement exists in the multi-tiered,
non-hierarchical topology. Traffic data may be estimated from the
aggregate volume through the peering points of the Tier 1 network
providers, but traffic that stays local in large provider networks may
not be accounted for.
Outages
=========
An Internet blackout or outage can be caused by local signalling
interruptions. Disruptions of submarine communications cables may
cause blackouts or slowdowns to large areas, such as in the 2008
submarine cable disruption. Less-developed countries are more
vulnerable due to a small number of high-capacity links. Land cables
are also vulnerable, as in 2011 when a woman digging for scrap metal
severed most connectivity for the nation of Armenia. Internet
blackouts affecting almost entire countries can be achieved by
governments as a form of Internet censorship, as in the blockage of
the Internet in Egypt, whereby approximately 93% of networks were
without access in 2011 in an attempt to stop mobilization for
anti-government protests.
Energy use
============
Estimates of the Internet's electricity usage have been the subject of
controversy, according to a 2014 peer-reviewed research paper that
found claims differing by a factor of 20,000 published in the
literature during the preceding decade, ranging from
0.0064 kilowatt hours per gigabyte transferred
(kWh/GB) to 136 kWh/GB. The researchers attributed these
discrepancies mainly to the year of reference (i.e. whether efficiency
gains over time had been taken into account) and to whether "end
devices such as personal computers and servers are included" in the
analysis.
In 2011, academic researchers estimated the overall energy used by the
Internet to be between 170 and 307 GW, less than two percent of the
energy used by humanity. This estimate included the energy needed to
build, operate, and periodically replace the estimated 750 million
laptops, a billion smart phones and 100 million servers worldwide as
well as the energy that routers, cell towers, optical switches, Wi-Fi
transmitters and cloud storage devices use when transmitting Internet
traffic. According to a non-peer reviewed study published in 2018 by
The Shift Project (a French think tank funded by corporate sponsors),
nearly 4% of global CO2 emissions could be attributed to global data
transfer and the necessary infrastructure. The study also said that
online video streaming alone accounted for 60% of this data transfer
and therefore contributed to over 300 million tons of CO2 emission per
year, and argued for new "digital sobriety" regulations restricting
the use and size of video files.
See also
======================================================================