I posted earlier on a similar topic.
I been experience a great deal of spam on my site and it is driving me nuts!
Although I use 'Goodbye Spammer' I need to manually remove it which
takes too much time.
So for now I have activation set to 'Admin Activation' so at least I could delete the obvious spammers.
At this point this seems like the most logical way. I would appreciate your input on this.
Thanks
http://mods.mybb.com/view/fassim-anitspam
http://mods.mybb.com/view/signup-questions
I recommend trying those plugins as well, and setting it to email activation. I also find, for spammers who like to re-register if banned, suspending their ability to post works wonders. They think they're still spamming, when they're doing nothing. You could make a group that isn't allowed to post in any forum, and set that as a banned group, so all spammers can be moved there.
Sign up questions + reChaptcha II