I think that people are missing the point. A comment's quality is not measurable by it's score. If anything, that is a rough aggregation. By this logic, Ke$h

I think that people are missing the point. A comment's quality is not measurable by it's score. If anything, that is a rough aggregation. By this logic, Ke$ha is a better musician than Joshua Bell. Top comments on HN were becoming more "top 40" and something had to be done before people started posting links to Trollface, etc. One approach would be to use category-based voting, which adds a lot of complexity. One approach would be to implement some sort of vote weighting sytem (time based, reputation based, context based), but that's ad-hoc and may not fix the problem. And one approach is to simply hide numerical comment scores from all but each user's own comments. This turns the quest for high karma into a personal battle against one's self, not a sport. PG wisely chose to make Karma a personal Everest for each individual to care about (or not).