I get lots and lots of comments tracking back to sites that are nothing but collections of links, including one to my site. They’re mindless enough that they’re probably automated. Though getting a link is nice, I always mark them “spam” because they don’t seem to serve any purpose. And its not as if they’re advertising traps, because the sites tend not to have advertising. So why does anyone put them up?
Probably spammers trying to cheat Google, which uses links primarily to decide how sites should rank in its results.