Well, now I know one of the products being used to create all of the referer spam I end up dealing with. Something called Reffy, found at http://www.reffy.net/. Even worse, my suspicions about why they do it have been confirmed:
Now, the premises behind the concept of referrer marketing are these: 1) all servers/hosts log the referrer information of the visitors coming to its sites; 2) an important part of all statistical programs is the displaying and linking of all logged referrer strings, which webmasters actively look at and click through because they are curious about what kinds of sites have links to their own sites; 3) a high and even sharply increasing number of websites, particularly "blogs", automatically link back to sites that have sent traffic to them in public "referrer tables" which surfers often use to find more and particularly relevant sites.
So to all of those people out there with those cute little "who's been linking to me?" scraps of code...fucking stop it.
And I would like to reiterate my position on spammers: they should all be drug out into the middle of the street, disemboweled, and then slowly beaten to death. Just because some people are stupid enough to listen to your spiel, doesn't mean the rest of want to.