This came to my attention earlier this week... I think somebody linked it on twitter. Anyway, Phil Plait is a skeptic, but the stuff he says about the ways people try to persuade other people on the internet, are worth a good hard look. Especially if one often finds oneself butting heads with other people.
Summary, and these are as close to the "golden rules of internet commenting" as you can find:
1. it's not what you say, it's how you say it
2. don't be a dick -- back in my "complaining expats" days, I once wrote that "when you talk so harshly, even when you're right, you're wrong, and even if you win the argument, you still lose"
Best line: "Is your goal to score cheap points, or is your goal to win the damn game?"