Augmented reality promises many things to me and possibly the most awesome and most devious is world-contextual advertising. While it sounds cool to be able to point your phone camera around your city and see information about locations I don't think it's really something were going to make regular use of, it's too clumsy even as it is a great proof of concept. What I find far more likely is that advertisers... say a popular restaurant chain, will have a augmented reality subscription service... or your regional heritage services. So when you are out and about and pass by a location of interest or a favourite eatery the days deals/menu/exhibits are delivered to your smartphone much like a text message. So you're passing the local gallery, your marketing profile says you're into Picasso and some of his stuff is on exhibition your phone chimes up, you're offered 25% off and given the option to download the audio tour.
The difficulty as with all targeted advertisement will be it's intrusive nature. Maybe it's not as cool as interacting with this virtual layer of over-reality but it has some other cool applications combined with geo-location. Alerts when your friends, Twitter follows, facebook contacts are nearby perhaps?
I suspect we might see some cool things in the next 18 months.