You might not have even known that it existed, but Amazon has its own social gaming network called GameCircle. It has been exclusive to the Kindle Fire platform, so you may not have ever heard of it if you don’t own one. Today, Amazon is bringing it to all Android devices.
Amazon first launched GameCircle a year ago, so this is a big move for the company, which will help them in the mobile gaming arena. Some of the features include: syncing game progress, achievements, and leaderboard data between devices.
GameCircle has been implemented in over 500 games so far. Those games all happen to be Android APKs distributed through the Amazon Appstore, so that makes it easy to have the features merged into the Google Play listings. Android users can finally check it out.
Source Phone Arena