This is already sort of implemented. But moderation is a very very difficult problem to be solved and there are different philosophies for it...

How about these? - rate limit overall messages, maybe even percentage wise: if some ip sent more than 70% of all messages in the last minute, mute it. - let other users mark/report spam and if three others agree something is spam, block all slightly similar messages for 24 hours? - forbid sending the exact same message more than N times per M seconds. - rate limit color change and jump much more.

Yeah, some of those are good ideas. I'll implement them. Thanks for the contribution! (Instead of just say it won't work, heheheh)