Winter '11 Force.com Platform Release
Security Sharing Sets

• Organize your authenticated sites users
• Provide profile-based access to your sites

Authenticated sites extended the functionality of your sites. Now admins can group users and target them with different levels of access to data. This approach lets customers implement key business models that require users within the same account to have different levels of access.

For example, a Service Cloud customer can give some management or specialist users the ability to see all cases under an account while still ensuring that most users see only their cases.