You may have noticed a large drop in the number of users. We've just pruned the memberlist, deleting any user that had never logged in. This has likely deleted some legitimate accounts, and missed some spammers, but it hasn't resulted in the loss of any content on the forums.
Apologies to any legitimate users who have been inconvenienced by this. We're cleaning up the forums, and this has been a necessary step. Feel free to reregister if you're account has gone missing.