Those last two question were interesting. XBOX is hardly casual gamming experience, but connecting up In Game Purcgaes, and Leadershop Boards for us Indie XBOX developers, in an XBOX Indie Marketplace is surely an opportuity. Plumbing up WP7, Windows 8, an HTML5 Broswrr games to Azure Services, AND Xbox would complete the pciture, and be consistent with the full MS Gaming Ecosystem experience.
Why not partner directly with PayPal on the Servcies side, to support a single Api for in App purchases. Why give all the credit to each Individual Markeplace/ facebook. But I guess Microsoft wants to play the good guy, and be fair, across all those Markeplaces