The measure and status of a user's ability to communicate and be communicated with at any given moment. It includes the reception media (voice, video, instant messaging), the user's availability, and the user's willingness to communicate by various means and through various people (even if a phone is busy, for example). It also takes into account the capabilities and characteristics of each medium (whether a phone is for business or personal use, or which cell site a cell phone is in at that moment). Presence information can be distributed to interested parties through a presence service when it changes. Some specific types of presence services are "buddy lists" and "instant messengers."
Presence indicates whether a Jabber Entity is available for communication. It includes basic Availability (i.e., online vs. offline), as well as status indicators that capture various Availability Types.
Presence indicates a Jabber entity's availability for communication. It includes basic Availability (i.e., online vs. offline), as well as more particular status indicators that capture various Availability Types.