Forums Spam

Question

We are looking into recent forums spam. We have located the IP address and looking into a solution. Some of the ideas proposed by Neel are:

• Do not allow duplicate title
• Do not allow numbers and special characters in a title
• Restrict user to a single question every few hrs or so
• Once a user is deleted or deactivated, remove all of his forum posts and article comments.
• Look for suspicious words and block them
• Remove Captcha. That doesn't help much.
• English language only
• Limit amount of lines unless it is code format

Any more ideas?