The way I've always thought about it is as the application of game mechanics to the problem of sustaining a community that links to quality content and produces

The way I've always thought about it is as the application of game mechanics to the problem of sustaining a community that links to quality content and produces quality discussion. Karma - particularly on Hacker news - is not useless - it's a concrete measure of the value you have added to the community. It's not a perfect measure - but I think it's pretty good. I'll very often follow through on looking up users with high Karma - finding out who they are if they declare it - subscribing to their blogs and things like that.