As it says in the title. I love it.
One of the worst (and most addictive) things on Reddit is karma - it encourages groupthink and one-sided debates.
Hubski's system is much better. I don't see a score when I look at the dots, it's more like a group of people saying "interesting point".
I very much enjoy it as well. As a new member it's quite refreshing to see a down to earth community that doesn't encourage the goal of acquiring fake internet points.