The Android piece is particularly interesting. If you're a publisher or developer with an Android app to promote, a Google+-authenticated user who is browsing around your desktop website will be prompted to download the Android app, too. Then, the user can opt to get an over-the-air install of the app without ever touching a smartphone.
Read more at http://venturebeat.com/2013/04/02/google-plus-login-button/#lOL2oCXRukFeFdM4.99
So Facebook wants to bring you content serendipity with Paper, a standalone iOS news reader app it revealed today that delivers human and algorithm-curated full-screen articles and photos in categories you select like Tech, LOL, and Pop Culture. Paper launches to everyone in the U.S. on February 3rd, the day before Facebook's 10th birthday.