Facebook just released their newest app, Riff, a collaborative video app that lets you create video clips, share them with friends, and see what new clip they add-on to it. You can watch videos made by friends, or join a video by adding your own clip. Riff is trying to let users crowdsource the next viral video. Think about viral video phenomenon The Harlem Shake. Sure it was shot lived, but more importantly, it was idea that was easy to copy, contribute and share. Riff seems to have it figured out by letting you contribute and share in a single app, making the entire production of these video memes as easy as possible.