BuddyPress.org

There is a new plugin I just found called BuddyPress Rate Forum Posts — https://wordpress.org/extend/plugins/buddypress-rate-forum-posts/. I haven’t tried it yet, but I plan to. It allows thumbs up/down voting on Forum posts and in the process users receive “karma points” for the quality and frequency of their posts. So, in theory, spammers would get bad karma scores from other users, and you could search for users with bad karma and then delete them.