[fragmede]

wow, that's all sorts of interesting.

You could also look at the commentors karma at time of posting a comment and a while after and guess at which comment got them the points.

[PaulHoule]

It is hard to tell because it might take a while for a post to get comments and in the meantime the person writes more comments.

It might be more practical to add up the score of a user’s submissions and subtract that from the total to get a comments karma score and then divide that by the number of comments to get an average which at least gives you a per-user rank which would be worth something.