If you haven't read the last two posts, do that first before you read this one.
While new avenues of media and enhanced interface possibilities for virtual goods sounds nice, there's a whole other realm of applications for this kind of technology. If the technology develops, these are sort of a given.
Physical items are limited by physical space. Normally, as much information as possible is packed onto a product, especially if the product and its packaging are intractable. The example I'll be using here is a can of pop; the packaging contains the UPC, nutritional information, recycling information, customer service information, expiration date, storage instructions, identifying information, and on top of all that it needs to look good so that consumers will buy it. And on top of that, it needs to keep the product pressurized and easily chilled. It's a miracle that a simple can of pop can convey all that information.
But there's a trick here, because it really doesn't. It relies on context. Nutritional information is rife with abbreviations, recycling information is usually limited to about 15 characters including spaces, and the UPC is worthless without a whole lot of information stored on computers. Here's another observation; my can of pop gives me far more information than I need. If I'm drinking a can of Mountain Dew, I generally don't need any information about it other than knowing the brand. And when I buy it, the only thing that the cashier needs to know is the UPC. So couldn't we increase efficiency by having two people see a different thing?
But having the consumer see one thing and the cashier see another is just the tip of the iceberg. In the virtual world, information doesn't take up space. We can fill the can with as much information as we want, having only some of it being visible at any given time. Not only can you include detailed nutritional information beyond the space available, but you can include customer testimonials, related products, special promotions, and a plethora of other things.
How would this work in the real world? I would walk into a store and see all of these products as they are now, but possibly with some mild animations on them. When RFIDs are cheap enough to print, they'll be on everything, meaning that the products will be communicating directly with my computer so that the proper effects can be presented. If I pick something up and look at it, this action will register with my computer and a floating web of options will be presented to me based on either my past choices (if my computer sees that I check the detailed nutritional information of everything, it might just pull that up automatically) or on most common actions at that store. The RFID chip printed on the product doesn't have to contain any information except a web address - once the computer has gotten that, it can link up to a computer that actually stores that information.
"But wait!" you say, "That sounds really annoying! I already hate flashing banner ads on my internet, and now I'll have them in real life?" Well ... that all depends. Just like banner ads can be cut out with the right add-ons, product information could be cut out too. It really depends on who has majority control over what does and does not get shown through virtual overlay. If it's the companies, then "dynamic marketing" is something you might have to put up with. If it's the people, then you should be able to walk down the aisles with nothing being displayed but gray bags and cans that don't entice in any way (overriding legacy information).
And with lenses you can do other things too. Drive-in movies can be arranged at arbitrary locations and with minimal cost, because there's no mechanical apparatus required. Posters wouldn't need to be put up, because you can just stick a chip to a wall that tells people's computers what to see. Better yet, you can just set it up to be completely virtual, so that the on-board computer accesses information about what should be where and gets it without needing to use RFID. Or if you're lost, you can simply call up directions from the net; with GPS, it would be possible to have the lenses project out a red line for you to follow*. Or if I'm shopping, my cart can bring up a virtual display that keeps a running total of what I'm buying. All of this requires no hardware investment beyond the cost of a computer, wireless internet, and lenses.
Scenery changes also mean that I can replace the view outside my windows with something more soothing; a lush jungle, a sunny beach, or silent woods. Replacing the view is still thinking a little too low level though; instead, I could make new windows, with the added benefit that they wouldn't leech heat.
Can you tell that I want it to be the future?
*This technology will be available on cars within the year, though it projects the line onto the windshield instead of your retinas.