[colins_pride]

I agree that filtering out the worst junk doesn't necesarily raise the overall quality to an acceptable level. It seems like there are two issues, which are related: [1] comments are too small-d democratic and [2] there doesn't currently exist a good mechanism for aggregating comments.

With the exception of a few places like HN, the best comments are treated about the same as bad comments. The absence of incentives leads to the absence of quality.

The other issue is related in the sense that if there was a good mechanism for aggregating comments across sites it would almost certainly serve to recognize and reward the best comments. Solve the fragmentation problem, and you get resolution on the first one for free.