The combination of distance and anonymity has led many threads on many websites to de-generate. At Political Science Jobs Rumor Mill, there is now a thread dedicated to pondering the question of why people are so angry. This piece on College Humor captures the dynamics well by using Billy Joel's "We Didn't Start the Fire." The video has much inappropriate language and pics (Not Safe at Work, unless you work out of the house and the kid is at summer camp), so hit the link only if you have a sense of humor.
There are larger discussions to be had about the role of the internet and its impact on etiquette and norms of appropriate behavior. Maybe some day.