Right - identifying AR as a hot area is easy, but formulating what that looks like requires vision. Money and talent will deliver the Palm Pilot (1997), vision will deliver an iPhone (2007).

My take on UX frontiers:

#1 text console #2 mouse & keyboard #3 touchscreen #4 camera & microphone

I think we're at the beginning of #4, and starting to see this in categories like messaging, social networks, dating, and e-commerce. I consider overlaying AR elements to a live camera feed to be a subset of this shift, but by no means the defining aspect of this new method to interact with machines.