Sorry for my bad english, frenchy
This is a old question that I wanted to propose something new. (if not already proposed)
It's for comment on serverfault.
I wanted to propose that we could display the number of helpful comment in the user profile page. (like for "helpful flags")
I propose that as I think that comment on server fault does not have the same value as on like stackoverflow. Some problem are hard to diagnostic if the user does not give enough detail, even with detail sometime, and a comment can easily lead to an actual answer. So we will not "reward" users with points that help with comments, but the statistic would be show.
Generally speaking if my comment helped someone to get an answer, I feel it helped globally the community. I see it as teamwork.