A mobile operating system for smartphones and mobile devices that serves as the successor to Microsoft's initial mobile OS platform system, Windows Mobile. Unlike Windows Mobile, Windows Phone 7 (also referred to as WinPho7) is targeted more to the consumer market than the enterprise market, and it replaces the more traditional Microsoft Windows OS look and feel with a new "Metro" design system user interface.
Metro's interface consists largely of a "Start screen" made up of "Live Tiles," which are links to applications and features that are dynamic and update in real time. The Metro design is also expected to be prominently featured in Windows 8 as well.
As with Apple's iOS, Google's Android OS and the BlackBerry OS, third-party applications can be developed for Microsoft's Windows Phone 7 and are made available through Microsoft's Windows Marketplace for Mobile. Microsoft doesn't enable smartphones running versions of the older Windows Mobile operating system to be upgraded to Windows Phone 7, and Windows Phone 7 also doesn't offer backward compatibility with Windows Mobile applications.
Windows Phone 7 features a multi-tab Internet Explorer Mobile Web browser that uses a rendering engine based on Internet Explorer 9 as well Microsoft Office Mobile, a version of Microsoft Office that’s tailored for mobile devices. A new update for Windows Phone 7 called "Mango" is expected to add a variety of critical new features, including visual voicemail, third-party multitasking, a fully HTML5-compliant Web browser (Internet Explorer 9 Mobile), integrated instant messaging via Facebook and Windows Live Messenger, face-detection software capabilities, custom ringtones, threaded e-mail and messaging conversations support and more.