The Online Presence Ontology (OPO) provides the main concepts and properties required to describe information about user's presence in the online world (e.g., on instant messaging platforms and Social Web sites).
The Online Presence presentation provides a quick overview of the main concept, OnlinePresence, the OnlinePresenceComponent and its subclasses Notifiability, Findability and OnlineStatus. The Notifiability component can be used to declare willingness of a user to receive notifications from applications (on which he/she is logged). Findability stands for the ability of other users to find his/her contact details in public listings while OnlineStatus represents the IM status, used on IM platforms. OnlineStatus in turn, has its own components that enable more precise descriptions of different statuses used by IM platforms. Those components are: Activity, Disturbability, Visibilty , and Contactability.
The Online Presence Ontology overview and the Online Presence Ontology Spec provide more details.
Applications Using the Online Presence Ontology (OPO)