What this suggests is that people put too much self worth in to their opinions and that most people simply aren't suited the rigors of arguing because they're too emotional (I'm no exception).

Being persuasive online requires people take the utmost care to the emotional distancing the targeted individual will have to invoke as they change their opinion but preserve their self worth.

pg touched off this in his essay http://paulgraham.com/discover.html

"The reason there's a convention of being ingratiating in print is that most essays are written to persuade. And as any politician could tell you, the way to persuade people is not just to baldly state the facts. You have to add a spoonful of sugar to make the medicine go down."