This is a great addition if you have vB3.6.*
http://www.vbulletin.org/forum/showthread.php?t=124828, that sure knocks em off the scale

Failing that, banning emal addresses is good. There is a huge list of them at
http://www.theadminzone.com/forums/s...ad.php?t=27175. Obviously some of those you can't ban from signup, but if you get a bunch from certain IPs, then ban the IP

We CAN beat em!