BuddyPress.org

I just recovered from a bad spam incident on my buddypress site. A user (who looked legit) suddenly started private messaging the whole community with obviously spam material resulting in some very angry members

I will go ahead and install Akismet and a captcha during registration H.owever, is it true that each user has to obtain their own key from wordpress.com and plug it into Akismet to get it to work? Is there an alternative that I can just activate for everyone? Or can I just provide all my members with my key to activate their akismet?

Also, what steps have other BP admin used to prevent the kind of spam that I mentioned above? I do not think Akismet & the captcha during registration would have helped in this situation.

Is there a plugin that flags users who message a lot of users in a short time? Something like that might help fight spammers.

Thanks.