In all cases since this became "a thing" the spam responders have different IPs than the OP. So this isn't a case of 2 people in an office making posts to each other. The IP doesn't get blacklisted but it could. That is something the spam service handles. It also handles how it decides to permit users to register on the forum. I'm sure its a complicated process. Anyways, i would wholly expect that spammers are using TOR to do their dirty work. And they don't seem to actually be bots that do this. They go about and fill out profile information somewhat randomly, with exception to that "flap" of Vista Business types we had awhile back. Anyways, I'm going to move this topic into Site & Forum issues.