From the Daily Beast   If mental illness were the key factor in multiple gun homicides, other countries would regularly experience similar acts of carnage. But they don’t.   In the wake of the terrible events of last Friday in Newtown, which left 27 dead—20 of them young schoolchildren—social media such as Twitter and Facebook played a key role in communicating the shocking news and expressing an international sense of outrage and grief. But they also spread misinformation and misapprehensions just as quickly. The gunman was initially misidentified, and his murdered mother was erroneously connected to Sandy Hook Elementary School. But while these errors of fact were soon corrected, a deeper misunderstanding took hold over the following few days as a shattered nation tried to understand an inexplicable tragedy.         Writing is seen on a home in Newtown, Connecticut on Dec. 17, 2012. The two funerals on…