Similar to the Twitter integration in iOS, Apple has also Facebook in iOS 6. With this integration in place, you will be able share a photo to Facebook right from camera app or post your location directly from maps. Facebook integration allows you to post messages, videos, photos, web pages, maps, and more on your favorite social network from a number of iOS apps, including Safari, Maps, Photos, iTunes, Notification Center, and more.
You will have sign in Facebook only once and then you can use also these features and more from any app without signing in again.