I've given the app a try, and it can be fun to flick through shots (although you may want a steady hand to avoid moving pictures involuntarily). The interface is simple, and it's easy to sign up, find your friends and share your creations. The challenge, I'd say, is convincing people that Swing will do something they can't already do somewhere else -- Instagram's Boomerang already fills a similar role, and a 1-second clip in Vine or Instagram itself might be enough for most people. Polaroid's app has the backing of Twitter co-creator Biz Stone, who's serving as chairman behind the project, but it'll only grow if people believe that leaving their existing photo services is worth the effort.