I had a brief conversation about this with Aikar, but the problem is that ChatMon, in its current form, can't solve this problem any more.
The only reason it used to work is because spammers weren't actively testing against ChatMon. If Aikar's suspicions are correct, and spammers are downloading ChatMon to test against, there's nothing it can possibly do. All they have to do is run it on one computer, and try to send tells to that computer from another and see what goes through. Once something goes through, they can safely spam it and it'll get through to every user of ChatMon. When a pattern to block that tell is added to the ChatMon rules, they just start over and find a new one.
The only way to make it work would be a total rewrite, using more sophisticated techniques similar to those used for detecting spam email. Simple pattern-matching won't do the trick any more if they're testing against it. Something like a
bayesian classifier would probably work, but would require large corpora of spam and non-spam tells, which I doubt many people have available, or would even want to share.