This looks to be damn cool. Looking at the docs[1][2] it's now possible to create a Spotify remote control (e.g. control PC from a phone) using the native client. Thinking about it, it's probably also possible to sync two Spotify players on different computers, although they would have to be using different accounts...
It would have been nice if the manifest.json used the Chrome extensions format rather than creating yet another one, but otherwise the developers should be congratulated on using plenty of HTML5 stuff, and what also looks like CommonJS modules.
I'm looking forward to seeing what comes of this!
[1] http://developer.spotify.com/download/spotify-apps-api/tutor...
[2] http://developer.spotify.com/download/spotify-apps-api/refer...
