Seems like psychologists have come up with a term that describes such effects as rude emails, flaming, and virtual shouting matches at online forums: It’s the “online disinhibition effect” at work. “In a 2004 article in the journal CyberPsychology & Behavior, John Suler, a psychologist at Rider University in Lawrenceville, N.J., suggested that several psychological factors lead to online disinhibition: the anonymity of a Web pseudonym; invisibility to others; the time lag between sending an e-mail message and getting feedback; the exaggerated sense of self from being alone; and the lack of any online authority figure. Dr. Suler notes that disinhibition can be either benign — when a shy person feels free to open up online — or toxic, as in flaming.” (source; my thanks to Jen for pointing this out to me)

It’s worth to quote from this article more juicy bits: “This work points to a design flaw inherent in the interface between the brainÂ’s social circuitry and the online world. In face-to-face interaction, the brain reads a continual cascade of emotional signs and social cues, instantaneously using them to guide our next move so that the encounter goes well. Much of this social guidance occurs in circuitry centered on the orbitofrontal cortex, a center for empathy. This cortex uses that social scan to help make sure that what we do next will keep the interaction on track. […] Lacking real-time cues, we can easily misread the printed words in an e-mail message, taking them the wrong way. And if we are typing while agitated, the absence of information on how the other person is responding makes the prefrontal circuitry for discretion more likely to fail. Our emotional impulses disinhibited, we type some infelicitous message and hit ‘send’ before a more sober second thought leads us to hit ‘discard.’ We flame.”