Videos with millions of views come in many flavors, but they have a common thread: they inspire us to share them with others. Viral videos have often provided decidedly ephemeral entertainment—think cats playing pianos and dogs riding skateboards. Yet TED is at the forefront of a burgeoning trend that puts ideas worth spreading high up on the list of things your friends and family simply have to watch. What makes users want to share a meaningful video? What drives success? With more than 750 million views to date, the TED case study illuminates some of the most important trends defining the new viral video.