1. Microsoft is in the mobile business because the mobile market is growing rapidly, with the number of smartphones sold increasing from 1.2 billion in 2011 to an estimated 2 billion by 2015.
2. Windows Phone provides an integrated experience across apps, services, and the cloud. It offers a consistent hardware and software platform to ensure quality and usability.
3. The Windows Phone development tools are free and allow building apps using .NET, XAML, and either Silverlight or XNA. Apps have access to the phone's capabilities and can be published in the Windows Phone marketplace.