Google has launched Google Play Services v1.0, a development platform for integrating Google services into Android apps. Those services include APIs for embedding sign-in and +1 APIs for Google+, as well as OAuth 2.0 functionality.
“The Internet already has too many usernames and passwords, and they don’t scale,” said Android developer advocate Tim Bray in a blogpost. “Furthermore, your Android device has a strong notion of who you are. In this situation, the industry consensus is that OAuth 2.0 is a good choice for the job, offering the promise of strong security minus passwords.”
Google Play services will roll out automatically to any devices running Android 2.2 or above over the next week, but keen users can now download it manually from Google Play. 
That means users running anything older than Android 2.2 (Froyo) wont be able to access these services. But Google isnt completely abandoning these platforms, as its latest YouTube update shows. Its bringing functionality which has been available for a while on newer vesions – including a watch later queue feature, and pre-loading for videos.
