Morons who post comments with nothing to do with the content and who's soul purpose is to get a free link drive me insane. Some do this so that people will click thus said links and generate traffic, others do it to raise the google ranking of their shit websites.
Of course, there's things you can do to stem the tide. I run MT-Blacklist and have an extensive list of things you can't post (and it's as up to date as you can possibly get). But there's always a new domain, new trick, new idiot who's trying to run the game.
Today I had to delete 30 new posts from a new domain not yet on the blacklist (well.. it is now!). This gets old fast, but my only other alternative is to block the abilities to post comments (and that's not gonna happen yet).
Of course, from time to time, I get a little satisfaction out of it. Some drive-by spammers use free webhosts and their actions violate the TOS of their hosts. I love emailing the abuse account at that host and turning their asses in
