For some reason, only about a third the emails sent by the forum since we changed servers actually go through, and even those are really really slow. As such, we can't have email verification of registrations enabled anymore. This has increased spam-bots tenfold. Image verification at registration is enabled. The better bots seem to be bypassing this, but if we didn't have it on we'd be getting ten times as many invaders. We do. They start new accounts and their IP is random. Yes, this. It's a lot more annoying for the admins than anyone else so I don't really appreciate seeing whinging about it anywhere other than Admin Discussion. There's nothing we can do about it at the moment.
If another sub forum named 'Bots' was created and put as the top section of the forums, would all the bots just post there? That way there could just be one big clean out daily or weekly or whatever.