We had methods where IP's are auto banned if registering with a banned email (means they have to swap proxies), proxy registers are forbidden (although good proxies cannot be differentiated from normal users, so they can get around it), email verification, image verification etc.
Best way to get rid of them? Everyone who registers goes into an automatic group. It used to be called members, but we created a new members group with the normal permissions.
The old members group, people can only post in existing threads.
After they've made their first post, they automatically get shifted into the members group (the new version) and can post/create threads etc to their hearts content.
All the others failed to stop spammers posting, they still register and get through (although we ban them as they join) - but not one spam message in nearly 2 months!
The other methods literally just keep our membership from being flooded with 20 new members per day (all spammers, not bots - but actualy people who register for the bots). The new group method means that successful registrants that are used by the bots to post will then be incapable of making a thread, and you don't get plagued.
It only works because, as i understand it, it's real people who sign up (low income apparently, whether you believe it or not) but once they've signed and done the email verification, the user info is loaded into the bot, which then goes off and does all the spammage. We used to get the spam post come several hours after registration at some points - so it appears to fit that pattern. Now they register, but when the bot comes along, it can't post its new thread
).
