The forum software has been updated.
The primary reason for this update was to get better anti-spam protection. The current setting is still somewhat relaxed, and a number of likely spam accounts had been created before this change so some spam might continue for a while until the accounts are deleted and the correct level of captcha has been found.
The forum is also changed to the default layout - I did prefer the old look, but by using the default layout it's less likely future updates will introduce problems.
Let me know if anything is broken!