A presence indicator is appended to every person in your contact list in the Launchbar and in the member list in each workspace.
A person's presence is determined by a collection of attributes that describe the person's status, activity, location, willingness to communicate, and contact information. Presence information helps you to contact others and helps others to reach you.
Presence indicators in SharePoint Workspace correspond to those you see for contacts in Microsoft Office Communicator. If a contact is not running Communicator, you see a subset of these presence indicators.