Randomizing the top three comments. Have three categories: New, Best (up:down ratio is high), Controversial (up:down ratio of 1:1). Pick one from each categor

Randomizing the top three comments. Have three categories: New, Best (up:down ratio is high), Controversial (up:down ratio of 1:1). Pick one from each category and then randomly make them the top three. For larger threads you can salt them into the top 10 comments. New comments that are truly good have a chance of being picked up to Best or Hot, and Controversial comments spur discussion and moderate the self-reinforcing circle-jerk that threads descend into.