Some of these are sleeper accounts, I wiped out a bunch yesterday but didn't clean out all of the PM's they had sent. Really, I banned 10 sleeper accounts along with a few others already banned.
XandderrMan is one of them.
Spam on the forum should already have been cut way down and should continue to decline as we get rid of the sleepers.
Sleeper accounts...
When a spammer find a forum, they create not just one, but several accounts. often spread over days. They only use one at at time to spam though. So while you ban one, the rest are still safe. Even an IP block isn't perfect. XandderrMan was part of a cell of about 30 accounts all owned by one person. At least 10 had yet to be used.
The email systems these people have been using has been blocked, their iP's have been blocked, most free email providers are blocked. Coming back in droves will be hard.