As there are many posts here on how to prevent spam, I thought I would share with you the things we did to prevent spam. Our board has guest posting enabled and we had a lot of spam. I then implemented a few mods and enhanced the word censor list and since then we have no more issues with spam. We allow registered or guests to post.
So, here we go.
1. Activate visual confirmation for signup: This is a key measure that prevents robotic signups. A MUST
2. Replace the default visual confirmation by a robot safe one. We installed "Advanced Visual Confirmation" from Amigalink which allows to configure the CAPTCHA with different fonts, random backgrounds, shadows, etc. This is robotic safe. Check readme and get some other fonts to add which makes it more safe.
3. Prevent double posts: Install snip that blocks identical subject posting. This is important to prevent robotic mass postings with identical subjects to multiple forum sections. See www.leuchte.net
4. Prevent comment spam: Install "DeterCommentSpam" mod which adds "nofollow" tags to all links. This will make the forum uninteresting as Google, etc. will not index the links. Has ACP configuration panel.
5. The secret weapon: bbAntiSpam. This mod will block all so called link posts. Usually these are posts with some story and a bunch of links. The objective is higher search engine ranking by posting long lists of links. This mod blocks them. Make sure you add words to the Word Censor list with replacement of "http://www.blocked.bbantispam.com
". That way they get blocked when the spammer tries to post. Following word is a must have: "/a" and "www". Beside that change all your other words to be replaced by the web link. See http://bbantispam.com
6. Optional: If you would want to allow guest posts, which you can when the above tools are installed, you should add the "Antibot_Guest_Post" Mod which adds a pulldown box in the post where the user has to manually set to "Yes" to be able to submit the post. It is not really required, but a nice function anyway that prevents robot posting traffic a bit.
With the above things on your forum you should see no more spamming. You can even activate guest posting and take a holiday
Any further comments or ideas please add to this thread. A spam free board is something really nice.