The new integration with Facebook will allow users to post photos to Facebook directly from Apple's Photos app, post their location from Apple's Maps app, and update their Facebook statuses using Siri. Apple will also show Facebook Events and Facebook friends' birthdays in the Calendar app and sync contact information between Facebook and iOS. "Likes" from users' Facebook friends will also be featured in the App Store and in iTunes to create a more personalized storefront. In addition, iOS 6 will make it simpler for users to sign in to apps using their Facebook logins: once they've entered their Facebook username and password under Settings, they won't have to do so when opening new apps from the App Store. (See photos of what the integration will look like here and here)
“We’ve been working very closely with Facebook to create the best Facebook experience ever on a mobile device,” said Apple's Scott Forstall.
Twitter got a significant boost from its integration with iOS 5, and Facebook is likely to reap rewards as well. According to Apple, a full 47 percent of all photos shared on Twitter are from iOS 5, and the micro-blogging service has seen its number of iOS users triple since the integration.