Looks like it's basically a mashup of the YFTY torrents api, a few other APIs for subtitles/metadata, and the peerflix nodejs lib for streaming the torrents. Done in node-webkit. The first commit was only 20 days ago, according to github (could have rebuilt history of course), and the most recent 3 hrs ago at time of writing. Seems pretty active.

It looks like "they're watching you" through Google Universal Analytics[0]. Not sure if that's something to be concerned about.

Sources:

https://github.com/popcorn-time/popcorn-app

https://github.com/popcorn-time/popcorn-app/blob/master/pack...

[0] https://github.com/peaksandpies/universal-analytics