OCS 2007 allows its client applications to publish and subscribe to Enhanced Presence information. The enhanced presence infrastructure includes categories and containers. State, note, contact information, or calendar data (e.g. Free/Busy) are examples of categories. Containers are logical buckets into which the clients publish the categories of presence information.
A user can control what presence information other users see. For example, if userA@fabrikam.com places userB@fabrikam.com in his Public container, userB can see only userA's name, e-mail address, and basic contact information. If userA places userB in his Personal container, userB can see detailed information like additional phone numbers, location etc.
OCS 2007 notifies watchers of presence changes for the container they have permission to access. OCS 2007 supports this functionality through the use of Access Control Lists (ACLs) that map a user’s contacts into Containers. Each end user can configure their ACLs via the “Access Level” or “Access Levels Management” view in the Office Communicator client. ACL’s can define the set of users which can access a container based on a number of different criteria[…]