Greater control over personal information privacy
The tech industry loves to gather our personal data, often unbeknownst to us. Apple gathers plenty of information about us in its stores, but in both iOS and OS X it provides strong controls to let us protect how our personal information is used by applications and Web services. The Security & Privacy system preference in OS X Mountain Lion adds to the location privacy settings in OS X Lion similar controls for access to your contacts, Twitter account, and Facebook account.
The first time an app or service wants access to these repositories, OS X displays an alert box asking you permission. If you say yes and later regret it, you can delete the untrusted app's or service's permissions in the system preference.