Forum spam raises its ugly head here from time to time so I've just installed the mass edit bbpress plugin to make life easier for all of us.
If you see a spam message, add a "modlook" tag to that thread. If the same spammer has spammed other threads don't bother modlooking them. I always dive into their profile to delete the account so I'll see the other threads.
On the other hand, if you've just spotted a spammer and the thread isn't tagged modlook, just add the tag. Don't worry about a spammer having more than one modlooked thread.
The mass edit plugin makes it really easy to delete all those posts in one go.
