Well, I just joined another vBulletin forum and they have an interesting method of keeping spam out.

I do not know if this forum does it since I joined it quite a while ago and do not remember or if it has been a new addition to all vBulletins. The first post does not appear until a moderator personally approves it. Hopefully this would keep out some spam and some of the dumb newbie posts.

 

vb has roaming groups, so you can setup a group that says 'trial user' and you'll be there till your 5th post, with all posts moderated. then after the 5th, it can automatically transfer you to 'regular member' group, which isn't moderated.

super easy to setup.

Though the spam here seems to have eased up.