Hi all, I've updated the ban list with over 1.7 million additional IPs. It's possible some legitimate users could be caught by the new lists - if you know of anyone having problems joining this board through the IP bans please let me know. The anti-spam signup challenge now also uses Google ReCaptcha, which was surprisingly easy to integrate. We'll see if that slows down spam automation.
A final step could be locking the board down to admin approval -- a user registers, and an approval request is sent to me or Jim before they can post. We may consider this if these new measures don't do the trick. Fingers crossed.