Facebook introduces the App Center, where we can find apps with Facebook integration in a single place.
The App Center will include any mobile apps, web apps, and “canvas” apps, which are the applications right on facebook.com so long as they follow Facebook’s developer guidelines. The mobile version of App Center won’t provide access to any of the web or canvas apps for obvious reasons. Also Facebook is launching a beta program today to give developers the option for in-app purchases.
The App Center will be way smaller than Google Play or the App Store because it essentially just acts as a filter to display only apps with Facebook.