Score vs. KarmaTiki has 2 ways of ranking users according to activity and popularity. They're the Score and Karma systems. They'll probably be merged in future.
In the karma system, users are given points according to other user's rating on their comments, and the more karma you have, more karma people rated by you will gain. It's a reliable measure of someone's popularity, by community itself.
In the score system you earn point's by your actions or other user's actions related to you, like reading an article, writing a message, creating a wiki page, having your topic replied in forum, etc. This is a quantitative measure, not by community but by computer.
|Points according to other users rating on published content||Points for every action, including other users rating|
|Reflects user popularity||Reflects user activity|