JS_Harris - 8:43 am on Sep 24, 2009 (gmt 0)

The trick isn't to sort the mail but to block the junk before it hits the mailbox.

All of the most widely used applications to help prevent spam are generally good but at the same time are the most widely attacked.

Customize your approach for best results. I find a lot of bots have problems with input boxes that are where they should be on any given site but are hidden so that a human wouldn't see it to type anything in. If a bot adds anything to it, ban them.

Custom questions work too, but nothing generic or mathematical.

Captcha works, but I find using captcha that doesn't come with the application works better. If a bot was looking for a particular type of forum it expects a particular captcha system, swap it out for something different.

The more you customize the fewer bots you will likely see. Human spammers on the other hand will get through but they tend to be hit and run types anyway.