As you've probably noticed, we've had a major spam attack over the past few weeks. I've tried a number of things to address this, and I _think_ I finally have some sort of solution.
I've set the forum so all new users are moderated, so any posts they make won't appear without approval. This is a serious pain for new users, but it also means spammers can't just join and post.
The software the spammers are using is pretty sophisticated though, and it has apparently been creating fake users for a long time, then days or weeks later the software returns and uses those accounts to post spam. As that happens I'm banning those users.
Eventually all the spambot-created fake users will be banned, and all new users will be moderated, so the spam should diminish quite a bit.
If you ARE a new user, and are a real person, just make a real post (real question, or real answer to a question) and as I moderate the posts and see something valid I'll mark your user as not moderated.
Hopefully this helps the spam problem.