Forum Getting Spammed .. Advice?

I can comment on what was done at another forum I was involved with (although I didn't do the actually "techy" part, so I cannot tell you exactly how to do it). Some of it didn't appear too tough, but we DID have some great technogeeks administrating that forum.

There is a very powerful forum spam software (from Russia, I believe) called Xrumer that is very difficult, but not impossible, to defeat. It can sign up by itself, defeat some captchas, verify emails etc.

Some potential steps to take:

1. Like you are already doing, require new users to supply an email and defeat a captcha. Require the email to be verified before allowing login. This might slow down some spam software and manual spammers (but not Xrumer).

2. There are addins (at least for Vbulletin, but probably for phpbb too) that allow you to set permission levels for users. Make all new users go through a "sandbox" of sorts, where EVERY post they put up (for the first 10, perhaps) require defeating a captcha. Use rotating styles of captchas (another addin) - various different kinds of graphical challenges, math challenges, answering simple questions ("what color is an orange?"). This really seems to frustrate both manual spammers and some of the software, which doesn't expect to defeat different types of captchas.

3. Require all new users to look at a specific post before they can browse or post in the forum. In that post, explain that they are "on trial" due to spammers, that their first 10 posts will require answering a captcha etc. This appears to confuse some of the spamming software too - it expects to navigate the forum, NOT to be stuck looking at a link that says to look at this post, then confirm that it read that post.

If you explain it as protecting the users from nasty spam, nearly all legitimate users will accept it, even though posting will initially be a bit harder for them.

4. Disable live links (turn off "parse html" or something similar), especially for new users. This frustrates manual spammers to no end, who are trying to get backlinks. It also prevents your forum from linking to the nasty porn site of the day...

5. Make sure your forum has a method for people to report spam. Make a post that you require EVERYONE to read, explaining the spam situation and asking for help. You would be amazed at how happy people are to report spam posts - it becomes like a contest or race (at least on forums that show spam reports under the "new posts" search). Be sure that moderators employ a "one strike your out" approach - any obvious spam post is deleted, all the other posts by that user are deleted, and the user is immediately banned.

6. If all that fails - yes, you may have to start moderating all new posts by new users. Terribly painful, and frustrates new users more than answering captchas...

These methods (except for #6, which we never implemented) seemed to cut spam by well over 90%. We also got some lurkers more involved in the forum due to the spam reporting (you could actually make it into a formal contest - even more fun!).

Of course, there are other more sophisticated methods, like changing the user interface into a customized one so that the spammng software doesn't know how to navigate the forum, but that is beyond most folks...

Best Regards, Georgetta