Facebook takes wraps off App center

The app store model is winning the evolutionary battle for software businesses. It is how operating system manufacturers are making ongoing money, especially on mobile devices. But now Facebook, which has a social-networking platform but not an operating system of its own, has figured out a way to take advantage of the model.The challenge, for a platform like Facebook, is that it has to build a store on top of these other existing stores. It is especially tricky to build on top of the Apple App Store, which remains the only legitimate channel for users to get apps onto iOS devices. Facebook will be selling three things: pointers to mobile apps on other stores; pointers to free web apps that use Connect; and actual paid web apps.