According to Rick Moran at Cisco Presence is near the number one priority. In a caption from Rick's blog via IT EXPO he mentions, "The application and the network need to work together better and it doesn't make sense that cell phones ring at 3:00 am local time when you travel as the phone and network realize what time it is."
This is an excellent example of the use of Presence. If the phone knows what time it is (which it does) then why is is ringing at 3AM ? Better yet why doesn;t the network immediately respond with an automated call or SMS back to the caller informing them that "Hey caller, it's 3AM, send me an email @ and I will get back to you at a sane time." Presence can play a huge part in the enterprise. It would be very beneficial for team members to understand what environment or what the status is of other members without having to do anything more than look at their phone or messenger. This way they would know that an instant message is not going to cut it, or maybe it would be very timely to send some critical business info to that team member during that meeting.
We have seen Presence in action via proprietary personal Instant Messagers for years; Yahoo, Skype, AIM, ICQ, MSN and there are others. Google has in some ways broken the proprietary chain with the introduction of GoogleTalk IM using XMPP for Presence and IM. I have been preaching open standards in VoIP, IM and Presence for a lifetime it seems and I am glad to see Google has gone in this direction. But did Google choose the right protocol/technology? Could SIMPLE and XCAP serve them better? It seems as though Google wants to support both SIP/SIMPLE and XMPP.
Here is what Robert Sparks - organizer of SIPit had to say about Presence during a brief conversation I had with him today. "The general opinion still seems to be that XMPP is good for right now for medium sized solutions. When people start looking at large portals and interdomain, they start looking at SIMPLE. You have seen folks like Nokia making more noise about OMA, PoC, and related things? Those tout SIMPLE pretty strongly." Robert is also the author of SIP Beyond VoIP. Chapters 5, 8 and 15 talk why someone might want to deploy SIMPLE, including the new possibilities it uniquely brings to the market. It's a great read, check it out.