The Internet undermines the quality of human interaction, allowing destructive emotional impulses freer rein under specific circumstances. The reason is a neural fluke that results in cyberdisinhibition of brain systems that keep our more unruly urges in check. […¶] Communication via the Internet can mislead the brain’s social systems. The key mechanisms are in the prefrontal cortex. […¶] In order for this regulatory mechanism to operate well, you depend on real-time, ongoing feedback from the other person. The Internet has no means of allowing such real-time feedback (other than with rarely used two-way audio/visual streams). […] This results in disinhibition: impulse unleashed. [¶…T]his disinhibition becomes far more likely when people feel strong negative emotions. What fails to be inihibited are the impulses those emotions generate. [¶] This phenomenon has been recognized since the earliest days of the Internet…as ‘flaming’: the tendency to send abrasive, angry, or otherwise emotionally ‘off’ cybermessages.
Source: wiktionary