"Contrary to what you may have read, Susan Boyle didn't go "viral." She hasn't gained circulation through infection and contagion. The difference between "viral" and "spreadable" media has to do with the conscious agency of the consumers. In the viral model, nobody is in control. Things just go "viral." In the Spreadability model, things spread because people choose to spread them and we need to understand what motivates their decision and what facilitates the circulation."