I have this idea that there is a connection between profanity and flaming.

If you allow profanity, people somehow act worse than if you don't allow profanity. Maybe it is because the profanity filter makes people think about their own behavior a little bit.

In real life, there are controls in place (social mores, employment, cops) that enforce certain speech and behavior. On the web, that isn't always so. Maybe the profanity filter moves people toward one form of behavior and away from another.

This conversation makes me think of the difference between the conversations you have in a coffee place and the conversations you have in a bar.