[vadimr]

I also realized that some of these users were pretty creative and using the homepage field in their profile to get backlinks and actually post a reply somewhere with easy questions like "how come the link is not working, I cannot download", their signature would have something and so would their profile with the link to their garbage.

Here is a SQL query that finds these parasites:

update `user` set usergroupid=14 WHERE `lastactivity` - `joindate` < 86400 and `homepage` > "" and `homepage` != "http://" and posts = 0;

86400 means 24 hours (in seconds, look up epoch if need further information), so basically find anyone who's lastactivity and joindate are within 24 hours of each other, their homepage field is not blank and is not just "http://" (this was a default behavior of older vbulletin or something as I noticed many older profiles were not blank but had "http://")

I've deleted about 20,000 accounts from my forum just by running these queries. I also disabled BB URL in Signature and Visitor messages and disabled memberlist and leaving visitor messages to one self.