The thing which is weird, unknown, magical, surprising, shocking, has the greatest chance to achieve virality. Not just digital but anywhere (Virality nowadays stands in direct reference to the digital medium). Suppose a horror film, the film feels more attractive till the point of disturbance is not shown, a poltergeist. A bandage trailing away behind the curtains, the mummy is not being shown. Supposedly a person whom you don't know is more interesting than a person you know well. But the catch like any other communication is that the content should be exposed to the right people.