1. Symbian 2. Android 3. iOS 4. Blackberry 5. Windows That's how the market share ranking looks now. Symbian is the leader, while Android is catching up fast. With the recent Nokia-Microsoft alliance, Symbian will be replaced by Windows Phone as the OS for Nokia phones. That's a BIG win for Windows. The mobile OS market will be a three-horse race: Windows, Android, and iOS. iOS - kids and hipsters Android - rollerblading hackers Windows - professionals and everyone else That's the inevitable conclusion of the three-horse race. Shall we say within 4 years?