I had been completely bored by ipv6 until I read this InfoWorld piece:

Recently, cows in Gifu prefecture were tagged with tiny networked devices to wirelessly track their movements and body temperatures for health and breeding purposes. And in Nagoya City, taxis were fitted with Internet-enabled sensors on their windshield wipers, allowing dispatchers to continuously monitor rainfall via wiper speed and to dispatch more cabs to the wetter neighborhoods.

There's a whole class of new presence applications right there.