[throwaway283719]

Interestingly, within the top 100 there is a weak positive correlation between the total karma, and the average karma per comment, implying that the people at the top of the leaderboard are actually posting quality content, and not just making up for it with quantity.

The closest power law fit is

  predicted average score = 0.27 * (total score) ^ 0.25

which has a correlation of about 20% with the actual average scores.

[simonster]

Either that or people with higher average karma per comment are posting their comments earlier so they get more upvotes. Or HN's comment sorting algorithm is privileging users with higher total karma, so those users have their comments appear above other comments that have the same number of upvotes. Or users with better name recognition are more likely to get upvoted.