In an instant messaging (IM) system, it is the status of a person's current availability (online, idle, offline, etc.). The status can be changed by the user or set automatically by the IM client after a certain amount of time without keyboard or mouse activity. "Unified communications" requires presence across all the applications and devices the user might communicate with, including e-mail, IM, office phone, cellphone and PDA. "Rich presence" implies conveying more information about the user's current status, including type of device being used and its operating environment, location and local time of user and any other messages the user might wish to announce. See unified communications, IMPP, XMPP and buddy list.
