Not general karma, in the true meaning of the word. But reputation on particular subjects, such as "has good taste in fantasy movies". And not summed; each measurement is of a vote given by one person for another person/thing/opinion. Because to use these numbers, you may want to weigh each vote by a person by your historic agreement with that person on that topic (or your estimated agreement with that person, computed from their scores and your scores, or recommendations of them by people whom you have opinions of).