I used to admin a vbulletin 3.8x forum. I ahd to do a ton of work into keeping spammers from one registering and then posting.
Two things:
Admins:
1/. go get an akismet key and activate the in the forums admincp
2. Look into installing the stopforumspam.com modification at stopforumspam.com.
between these two I managed to nearly eliminate spammers form the forums.
