An interesting approach of using your Google(+) Account for signing in into different services.
What I really like about this particular system is that it (can) gives you the opportunity to select with whom you’ll share it with. So it’s not like all those annoying Facebook apps that instantly spray your friends with spam posts.
Another important feature, well it looks like that at least, is that you can directly choose to buy or listen to something. So for example, you’re listening to a song on Spotify and it’s $2,99. You think the song rocks and share it with your music circle. Everyone in that circle can directly click and buy the song directly!
That’s not only great from a developer’s stand, but also for the consumer. He gets a one click approach without a lot of hassle As quickly as possible to the content you want!