Apple is known to go to great lengths to protect their secrets and prevent leaks about their products before official launch, and that's why it is ironic that their anti-leaks policy document got leaked.
The document was leaked by 9to5Mac website and - surprisingly enough - it is not as over the top as one would expect given Apple's reputation.
The policy states mainly that Apple employees "may not disclose Apple confidential information to an outside party unless a written agreement or license has been previously signed and approved by the division vice president."
Additionally, the policy directs the employees not to use their @apple.com email addresses for non-business-related matters, with alternative @me.com email addresses given for use in personal communications.
The policy allows Apple employees to have their own blogs and websites as long as they don't discuss anything about the company or its products. As for social networks such as Facebook, Apple employees are required to "be thoughtful about how you present yourself in online social networks. The lines between public and private, and personal and professional are blurred in online social networks."