Veritasium [1] has a very interesting video about Facebook likes [2] (link via Hacker News [3]) and how, in an odd way, they can actually lead to less views of a Facebook page, especially if you buy “likes.”
And don't think Facebook will want to clean this up any time soon, as click farms benefit Facebook (Facebook makes easy money). This is a real case of “buyer beware!”
In addition to this, you should be aware that you aren't seeing everything on Facebook [4], due to its filtering. Just saying …
[1] http://www.youtube.com/user/1veritasium?feature=watch
[2] http://www.youtube.com/watch?v=oVfHeWTKjag
[3] https://news.ycombinator.com/item?id=7211514