I'm starting to get lots of spam on one of my forums. Only members can post so I don't know how they're getting through the membership system to be able to post spam like poker and gambling. These are clearly bots. I've seen some of the URL encoding that didn't work in the posts.
They're coming from everywhere on different domains that I have. I'm not sure an infinite number of rows will be enough to list all the domains to ban.<
You might be able to get some help from here, here, here, and here.
In these and a few others there was mention of a MOD that makes the users enter the text contained in an image, and a few other tips tricks, et al. (IP Banning/including their domains as bad words/etc.)
Also, marcel's MOD might at least help cut down on some of the spam.<
I use to get u-yep.com spam all the time, but the anti-spam mod took care of that. You know, the picture-word verification thing in order to register. It works swell!<