The Spam Destroyer plugin now features experimental support for bbPress user registrations, bbPress guest posting, BuddyPress posts and commenting and WordPress multi-site user and blog signups. If you test it, please leave a comment below. I’d love to hear how well it works. I don’t use any of these features myself so I have no way to verify if they actually work in a real-world scenario. In principle they should work quite well, but it’s impossible to know for certain until someone guinea pig tests it on their live site :)

Spam Destroyer plugin