Instagram is coming out with a new app called Boomerang that lets people share one-second silent mini-videos. The obvious comparison here is Vine, but Boomerang won't have its own feed — instead, you post the mini-videos on Instagram or Facebook. So it's a tool, not a social network.
Boomerang doesn't do anything Apple's Live Photos doesn't do — just like Live Photos, it stitches bursts of photos together to create something that looks like a GIF. It's taking the Live Photos concept and making it easier to share them on Facebook's apps. (The Boomerang videos will also save to your camera roll.) It's also very similar to Google Photo's animation feature, which knits photos together to create little videos. So nothing here is new but the packaging.
Why not just add this as a feature to Instagram? Facebook has been cautious about bloating Instagram with extra features, which is why it spun Hyperlapse into its own app. Boomerang is probably a standalone for the same reason.
I'd personally rather have fewer apps that do more, but maybe I'm in the minority.