I truly believe that presence is an important enabler for applications, and the example I was thinking about in the last presence post was Iotum's Talk Now. (In full disclosure here, I am on their advisory board, which means that I really believe in what they are doing. I expect no material benefit from the Iotum relationship other than the satisfaction of seeing good people and good technology succeed.) For those of you not in-the-know, Talk Now is an application that you use to tell people when you want to speak with them, and when you can take their inbound calls. Essentially, it helps to make sure you connect with the people you want to. This helps you reduce anxiety around your communications, because you can have some confidence that the calls you want to take, you won't miss, and that you have some power to control when that happens.
Due to disintermediation, I expect that the handset vendors will have an outsized portion of the value chain in next generation communications. FMC efforts will ensure that the transport layer is quite generic and reliable, giving large wireless carriers little room to charge hefty connection fees. The handset, and applications that run on them or are enabled with them, will be where the game is at. Any application that leverages that is gold.
This is a powerful thing, really, and just like Ken Camp said, I would expect the likes of Nokia or Motorola to jump on this bandwagon by snapping up places like Iotum. This is a double win for each presence enabled application they can snap up. It gives them real value that can be leveraged without the permission of the carrier, and it keeps it out of the hands of their competitors.