A couple weeks ago, Mat Honan wrote about the most viral people on the Internet. At the top of that list was Maxwellhill, the first and only Reddit user to achieve 1 Million link karma points—link karma is the unit of measure of a Redditor's story-selection.
Sometimes a story or idea goes viral because it's too big to be ignored. But more often it's because a single human being passes it along to an audience that's either massive, highly influential, or both. There aren't too many people who can do that.