[tim2]

Even the least skillful trolls mask their ill intent by blending in and maintaining a non-descript tone. This is done in order to get past the "human spam filter." If you run stupidity detection based purely on the contents of their comments then you run the risk of simply banning controversial topics or people with bad spelling instead of controversial (trolling, roughly) behavior.

To better detect trolling behavior, I'd focus on responses:

- Content of the responses. Lots of shouting? Length.

- Number of responders. 50x more replies than you would otherwise expect from the thread?

- Depth of thread. Conversation still dragging on after all sane people have left?

- Timing of responses. Heated arguments leave no time for cooling off.

So measure effect of the troll, and your system won't have to try to understand what he's saying.

+ But you were referring to "stupid" measuring based on the submitters data may work just fine.

[abstractbill]

All of the above also apply to running-joke threads, which I'm quite fond of as long as they don't take over a site completely.