>>sharps+(OP)
On news.yc it is not so extreme, but on german tech news site heise.de, there is also a modding system. Good threads become green, bad ones red. I have often wondered if people are more likely to start flaming away in the red threads. Sort of like beating up somebody who is already down on the floor (comments on the line of "you suck"). At heise.de I often had the impression that it is the case - not so much on news.yc, but it might be interesting to look at the statistics?