I know this has been suggested before, but I think the best way isn't to just kick out spammers and idiots, but to keep them from coming in altogether. Perhaps a special forum will newbies have to proof their intelligence before they're allowed to submit, rate, or post? Similar to what the old Acmlm's Board had before letting people into the hacking forums. There could be a special group of trusted users to moderate the forum so the actual moderators don't get overwelmed.
NNID: JoshButton (Nickname: Buttons)
SMM Bookmark Account: Click here. Many fun levels to play! :)
NNID: JoshButton (Nickname: Buttons)
SMM Bookmark Account: Click here. Many fun levels to play! :)