And that's a very good reason for a developer not to use platform specific account systems. It seems relevant that the top grossing app on iPhone (Candy Crush

And that's a very good reason for a developer not to use platform specific account systems. It seems relevant that the top grossing app on iPhone (Candy Crush Saga) prominently has this on their homepage: "Start your game on Facebook or mobile and seamlessly continue your saga between platforms. Your game play will be fully synched across all devices."