With the release of OS X Mountain Lion, Apple added loads of new features into the operating system. This feature is called Sharing. Sharing allows you to sign into your multiple social networking accounts and use them system wide to post status updates, photos, videos and links in many applications.[youtube http://www.youtube.com/watch?v=6CFFiLej2YM&list=UUCloQNUuEMGLKC9jNcb3leQ&index=1&feature=plcp]
According to Apple’s website, you can also sign into Facebook but that feature will be coming this fall – most likely with the release of iOS 6.