Do I really expect to mess up spammers that much by setting my backup MX (Mail eXchange) record to 127.0.0.1 [1]? To cause their servers to melt under the load of ever lasting spam circulating through their servers, perpetually delivered back to themselves for anohter round of attempts?
Not really.
First off, the spammers that are sending email to the backup MX server is already using custom (or customized) software to begin with—the SMTP (Simple Mail Transport Protocol) spec states that servers contact the MX servers in priority order (with the highest priority one being considered the primary), which is something the spammers aren't doing.
Second, it's likely that they're using botnets [2] (large collections of compromised machines) to do the actual sending of email, and the chances of the machine in question running an SMTP server are pretty low. So the likelyhood of me causing their servers to melt down are very low.
What I am expecting to see is a drop in the number of spams I receive. And possibly causing a headache or two (hopefully).