If you run WordPress, have a look at your admin screen Edit > Comments. I am deleting hundreds of comment spams, and a lot of people are being hit hard. I didn't turn off commenting, just made any comments with over 1 link go into the moderation queue, and added a few words to my filter.
Wordpress moderation features out of the box are pretty good, and if you want more there are plenty of plugins. Right now, I figure trying out plugins will take more time than deleting spam so I'll stick to that.
# Nov 10, 2004