Extending mobile presence - the need for context and device state information

I speak to a broad variety of vendors and operators about presence in a mobile context. It crops up repeatedly both for operator-centric developments like IMS and RCS, and also for independent applications like mobile VoIP and corporate unified comms. In theory, mobile phones ought to be good platforms for presence information - both rudimentary connection details (online, offline, idle etc) and some personalised state or emotional content as well ("Dean is currently thinking about lunch" and s