Facebook are creating their very own version of a central app store similar to that of the Apple App store and apps for android. This would put all of the apps that are available on Facebook in one place where people will easily be able to find them, and the apps used by their friends. They already have tons of them, most well known would probably be apps such as Farmville and Poker. More and more apps will most likely be developed especially for Facebook if they are now all in one central location.
Basically the App Store for Facebook only. Nice one, Zuckerberg!