Full post here: viewtopic.php?f=2&t=6339&start=20#p58685
This is what we're doing:
We have updated the forum software, including the anti-spam plugin that connects to stopforumspam.com database.
We have also added recaptcha to the registration system, so in order for a spammer to get through, they have to be coming from a 'new' IP address that has never been reported for spam before, and they need to be a human clicking on the recaptcha and also confirming their account with a valid email address.
We could make all new users go through a manual moderation process before they can post, but that's a lot of work. It's a different type of work I guess - one is deleting spam junk, the other is approving valid junk
Might be the way to go...