Android's swelling collection of "augmented reality" applications got a boost the other day when Layar hit 2.0. Layar's probably the most advanced example of its type, combining live video from the phone's camera with data overlays for local points of interest. Part of what makes Layar so interesting compared to its competitors is that it has an open API for developers to create their own overlays. I'm sure you're as excited as I am for the eventual branded or ad-driven layers.
This kind of thing is a deeply attractive technology just because it's so visceral--people love to consider the implications of digitally remixing (or obscuring) their surroundings. But the current fashion of doing so in a literal sense is probably a dead end. At the very least, it prompts a vision of annoying tourist hordes wandering around the city holding cell phones in front of their faces, like superstitious villagers waving the cross at their surroundings to keep the evil eye at bay ("evil eye" is actually not a bad term for the abuse of AR tech). Worse, to restrict the term "augmented reality" to that kind of hallucinogenic literalism misses the point, and squanders the potential of AR as a sixth sense by cramming it on top of our visual range. I'd argue that we've had augmented reality for a while now--and that it comes wrapped in a more appropriate level of abstraction.
Take Astrid for example. Astrid's another Android program--in this case, it's a to-do list/reminder system. On its own, Astrid lets you set timed tasks, tag events, and synchronize your reminders with Remember the Milk. But if you combine it with Locale, Android's location-sensitive alert system, now you can have reminders triggered by physical proximity, like entering the grocery store or coming home from work. Although there's no camera involved, and no sexy floating map, this is also augmented reality. Indeed, if you look through Locale's plugin selection in the marketplace, there's a wide range of intriguing possibilities: from waking your computer when you walk through the door, sending an HTTP request at certain locations, or keeping people posted of your location via Twitter or SMS.
Not to mention the concept of networked notation: really, I should be able to "tag" my current location and read tags posted by other people (see also: GeoBuzz or, to some extent, Ushahidi). This includes recommendations/warnings for nearby businesses, event recordings, historical information, and helpful hints ("Don't try the brown acid!"). It's the virtual equivalent of a message board, wherever you go, but sortable, searchable, and omnipresent. And that's the kind of sixth sense that's actually useful, because it gives you a local's situated knowledge no matter where you go.
If this still sounds kind of boring compared to the Virtual Light fantasy that Layar and other visual AR programs are pitching, that's because it is. But it's undeniably more effective than waving a phone around and hoping to spot a clue. Likewise, if I'm in Paris and looking for a good bakery, being able to see the relative position of my destination doesn't help me when the AR overlay neglects to mention that it's across the Seine. What I need in that situation is a good digital map--a less futuristic, but undoubtably more versatile form of augmented reality (and one that's available to anyone with a smartphone right now).
A while back, BMEzine ran a story (subsequently picked up all around the Web) on living with magnetic implants (note: link contains disturbing images). In this scenario, crazy people have neodymium magnets embedded in their fingers, giving them the ability to "feel" electromagnetic fields from computers, security sensors, and power cables. The author describes it as a relatively subtle perception, but one that gives access to a rich array of new information. To me, that's the model we should be using when building augmented reality applications. It's not about giving you a window into a garish world of digital overlays, but about simply providing context and knowledge in a given area.
Sometimes the best technologies are a lot less flashy. The cyberspaces of Gibson and Stephenson are a lot cooler than the textual Internet, but in a pinch I'm pretty sure which one would be more adaptable and innovative. So it goes with the augmented reality craze: when the dust settles, I think we'll find that we've been doing this in better, less literal ways all along. We're symbol-using creatures--abstractions are our friends. Let's use them.