The forum received a little spring cleaning today.
All spambots have been deleted as well as all inactive accounts which didn't have any posts yet. The integrated captcha was replace ReCaptcha to make registration for bots more difficult.
If you were a legit user and your account was deleted, I'm sorry about that. You are free to register again, your email address is no longer in the database so you may use it again. To protect your account from being deleted again, you only need to make a single legit post in any of the forums.