So, what exactly gets us hot and bothered on the 'net? Researchers at China's BeiHang University looked at the usage of emoticons on China's Sina Weibo (which is China's answer to Twitter) in order to gauge the most viral emotions — that is, which emotions spread most quickly and broadly through the network. They found that, while joy moved faster than disgust or sadness, anger was by far the most viral. Anger, it turns out, is the emotion most likely to cause a chain reaction in which one user's upset spreads to others and builds in intensity over time. That explains the Twitter-battle thing.
And, perhaps unsurprisingly, Internet rage often has very little rational basis. A separate study conducted by researchers at Wharton looked at the virality (in this case, the amount of shares) of 7,000 New York Times articles. They found that, regardless of the actual tone or content of the story itself, users would be more likely to share something if it happened to make them angry, while articles that made readers sad got fewer shares. This is because anger is considered an "activating" emotion — that is, it fires people up enough to take action. So, now we know where all those rage-filled hashtags come from. (Smithsonian Magazine)