The Power of Presence
Now, developers are looking to apply presence tools to other forms of communication. For e-mail, there's Convoq ASAP, a web conferencing tool that allows users to embed links in their e-mail messages letting recipients know if that user is available (similar to the way Yahoo! integrates its e-mail and messenger tools). Even phones will be able to apply presencing features with what is essentially beefed-up Caller ID.
Presence can be added to most forms of communications technology. With RFID tags, presence can be automatically integrated; an IM tool can tell your buddies not just that you've stepped away from your desk, but exactly where you are in the building. Coupling that with GPS tracking can take the concept to a ridiculous and unsettling (but not implausible) extreme.
The real question is going to come when we've decided we have a little too much presence in our lives. How are we going to turn off presence tools, or at least control what they say? Will we, as individuals, have the right to control our own presence, turning it on and off at will? And once we do that, will presence lose its effectiveness?