http://searchyc.com/user/**** (replace stars with username).

That'll give you # of comments, # of submissions, average # of points per comment, and average # of points per submission.

Average Karma per utterance would also be interesting. Or, indeed, per word.

I think Karma is a deceptive number. A high value for total karma of a site could just as easily indicate a dilution of value as an increase in value. Averages per user, per comment, per word, and per minute online would probably be more meaningful.