I can only speak for myself, but here's how I give out my 2 positivization points-per-click and how I give out my 1 negatization point.
In order to get a positive, I look for a post that shows some analysis. New spin on issues, playing devil's advocate on an issue, and making connections between observations. I'll also positivize for humor, so if you get me laughing, you get 2 points.
I'll only negatize for repetitive comments, complaining with no real analysis (exception on the game threads, where I think it's more about stream of conciousness writing than anything else), or personal attacks.
That's just my view.