Hardly a new type, they have been popping up for years.
Some of the spammers work really diligently, a couple of times recently I have logged in and found dozens of spam posts have been made by a single new member, one spammer even managed to reach "Senior Member" before he got banned!!!!
They have obviously found a way around the registration system and dont mind waiting 40 seconds between posts, although that "Senior Member" seemed to have found a way around that as well - according to the post times.
Time for Mark to have another re-think.