First of all, I know this has already been posted. But the thread's closed and I've got something to say.
I've got 9 personal messages- all of which are from spammers. I get e-mailed daily. Yeah, I know I can shut off the e-mail notifications. Don't worry, I have. The thing is, I wonder if other members know how to.
I ran a vBulletin forum for over three years. I setup a system that stopped HUMANS, real HUMANS from spamming my forum. The system is very easy to setup and doesn't even involve captcha's... it's all common sense.
There's a promotion system in vBulletin. It's very useful for sorting new members and confirmed new members. My suggestion is to restrict PM access/anything else that can be spammed to vBulletin's registered members. Have all posts be approved, no PM's allowed, profile comments approved/turned off, etc.
Then, have a message notification at the top of the forums explaining that until they make a certain amount of confirmed posts (mine was 3), they will be restricted from blah blah and blah.
Your moderators can approve the members posts. Once you see that the member is not a spammer and actually is on the forums for a real reason, use the promotion system to promote the member to a confirmed member group that doesn't have restricted access. The promotion system runs by default once an hour so you won't even have to manually promote them. Just have your mods confirm the posts and bang, depending upon the time that you set, the member begins confirmed.
This will really cut down on the spam and probably will actually cut down on the members who post just to hate. Another suggestion is to not reveal the amount of posts needed to become confirmed. This is sometimes necessary because some members, at least my forum, figured it out and faked to be nice/real/etc. (computer spammers can't do that obviously) until they became confirmed.
Just my two cents. Hope this didn't come across meanly, I just am interested in helping WB stay clean and organized like it should.