I've written a LOT of posts on AR that I don't post, but I'd like to briefly discuss a slightly advanced reason that AR will change everything.
AR is, at least in early stages, almost entirely about tagging. This is what everyone thinks about. People tag restaurants with reviews, billboards with party plans, street corners with historical info, whatever they want. This is all well and good, and it could evolve into some extremely useful stuff, but the killer app for this kind of tagging is tagging people.
The difficulty with tagging people is that people tend to move around. So you can't simply record the tag as being at a specific spot: you have to assign the tag to a specific person and it has to somehow follow them around. If you don't mind limiting tagging to other AR-users, you can probably set up some kind of ident broadcast, so you can look up tags attached to their identity. There are other methods, but they're a lot clumsier.
Anyway, the point is that you can tag people.
This is a whole lot more useful than tagging places or things. It's an instant reputation, first off: you can look at someone and see what people think of them. Second off, it's great way to know what people's interests are... because I can easily tag myself.
If I'm walking down the street with a "let's have lunch!" tag, everyone on the arnet will see that I'm looking for lunch and would probably be happy to have it with them. Furthermore, they might see tags like "science geek", "go-go-gadget-genome!", "www.projectperko.com", "who wants custom ARt?" (That's, um, augmented-reality art. ARt. I just pawned it!)
This can be further strengthened by having contextual tags. For example, I might limit the "let's have lunch!" tags to only people I've met... or only people with some of the same interests, or only people with more green tags (like) than yellow tags (dislike). This means that if someone sees my "let's have lunch!" tag, they can feel fairly confident that I will, in fact, be happy to have lunch with them specifically. Talk about an ice breaker!
Those kinds of tags, mixed with the reputation tags, allow a far higher rate of connection between people than otherwise possible. People can easily connect to me, but they also connect to anyone who's ever had an opinion on me, via my tags. They may also have opinions on some of the people who have opinions about me, and that might diminish or strengthen the tags those people have attached to me: it can be a very complicated situation, but it's made completely transparent, and the end result is that anyone looking at me will know who I am. Not just my name, but what I act like, what kind of circles I move in, what kind of accomplishments I've had...
I think that would change the nature of community!