Jabber, Inc. has a white paper on Presence and a press release on their intention to “introduce an advanced product suite designed to add presence and real-time communication capabilities to wireless devices and services.”
An extract from the white paper:
One of the most overlooked aspects of the Instant Messaging (IM) experience is presence. Presence is one of the key differentiators of IM
from the e-mail experience, along with low-latency transmission. It allows my friends and co-workers to know if I am attached to the network before trying to communicate with me. Presence is what makes IM feel instant.
Presence is not just for IM, though. This whitepaper discusses the attributes of XMPP presence that are applicable across a wide variety of applications. By the end, we will see that XMPP is a global infrastructure for presence.