I got almost annoyed with the continuous spamming (still happening at the time of writing) at Stack Overflow. More than anything else, this seems like a limitation with the system itself, which don't seem to have any built in support for preventing spamming.
The message contained abusive text, but from the behavior, I infer it is pretty human, it is not an automated bot.
Here are few thoughts
1 - User should not be able to ask more than one question per minute
2 - If user asks more than a limited number of questions in a short time, captcha should be shown
3 - Check for abusive words in the input, and if found a multiple times, suspend that user automatically for some time
4 - If a number of users are getting created from same IP, prevent the activity for some timeCalling @CodingHorror to do something urgently
Update: Seems like SO is working good now, after being down for some ten minutes. The spamming trend lasted for close to 30 minutes, and then Pretty good recovery, but need to think how to prevent this in future.