I think that karma could potentially be more useful as an assessment of the quality of a post if it were assigned more judiciously than it is currently on just about any karma based site. It might be possible to refine the karma system to improve it. It does not seem to me that the possibilities have really been explored. Currently, karma tends to enforce groupthink on most sites. On digg and reddit, I see massive groupthink. Both sites have become useless to me - they've become a mix of self congratulation, juvenile humor, and predictable politics. I remember when they found interesting stuff on the web.