I think it's only on iPhone right now.
It's like Instagram w/ 6 second video clips that you can start and stop recording, then in your newsfeed they will loop just like .gifs...with this site's affinity for .gifs, I'm sure people here would love another reason to waste more of their time.
It's a very simple app, I'm actually starting to like it more than IG already.
List your username!
Mine is just "Paul Brown".