I think you guys are missing the point here - and discussing stuff without any knowledge.

To give you some:

1. Anyone accessing has to pass our firewall
2. Anyone accessing has to pass our IP-filter
3. New registrations need to pass Stopforumspam
4. New registrations need to pass all other sorts of checks in forms, do math and so on
5. Newcomers need to fill a current google captcha and pass akismet's filtering until the 6th post
6. Proxied IPs are demasked if possible, public proxies get listed in blacklists too.

The blacklist is there to prevent mass-registrations by farms, the registrations are scripted and a pool of minions just solves math and captchas and what else.

No forum upgrade what so ever will let us get rid of the blacklist, what it might get rid of is the now frequent single link single post spam we have for a couple of weeks now. Last patch was applied yesterday btw.