It's interesting from a psychological point-of-view (sorry, it's what I'm studying).
It kind of reminds me of the de-personalisation that factors in to cause road rage. Everyone drives around in their cars, sheilded from everyone else in their own little 'car worlds', so it's easy to forget there are actually other humans just like yourself driving around.
I remember reading about an interesting psychological experiment where they tested to see how many motorists would honk their horn when a long line of cars were stopped at a red light and the car in front didn't go when it turned green. They found almost 90% of the time, people second in line honked aggressively at the first car.
Then the experimenters had a pedestrian cross the street between the first and second cars before the light turned green. Still, almost 90% of cars honked. Then they put the same pedestrian on crutches and had him hobble between the two cars. He was still out of the way before the light turned green. In this condition honking went down to 57%. Why? Because it instilled a sense of empathy in the drivers.
The same thing seems to happen online.... social inhibitions, empathy, nonverbal communication which are all so important for social interaction, can easily go straight out the window when there's de-personalisation happening.
That's my two cents
Carrie