Microsoft is taking its relatively new role as a mobile app maker pretty seriously. So much so that it's bought Xamarin, a company that specializes in cross-platform application development. The platform uses a shared C# codebase to "write the full set of native APIs and mobile capabilities provided by each platform," according to Microsoft's Scott Guthrie. In English, that basically boils down to "apps that run really well across Android, iOS and Windows." Satya Nadella and Co. have utilized Xamarin before, of course, on the likes of the Azure cloud platform and Office 365.