First, we used our phones to scan simple barcodes, which gives you text information -- the product name and how much it costs.
Then we went to QR codes, a 2-dimensional code that provides pictures and links to locations on the Internet.
Today, forget the code. We can get information from simply pointing the camera at a picture and add 3D information to the real world.
"You're never looking down at your phone; you're always looking through your phone," says Trak Lord.
That's called augmented reality, and it's the specialty of his company Metaio, with offices in Munich and San Francisco. It makes mobile and non-mobile apps for tracking natural features, including faces.
Recently we went beyond the camera to add other sensor information, such as geolocation, so that you could overlay 3D information on the real world -- for example, to find a place to park. In the app we tested, a red car icon indicates that a spot one street away is taken; green that it's available. 3D information layered on city parking sensor data. It relies on information about where you are.
The next step goes beyond images, to track actual 3-dimensional objects in the real world.
"We're actually tracking objects now," Lord said. "We can successfully track, say, a printer. We built a model city, and we were able to track it and overlay everything on it -- cars, billboards, storefront sale information. We're teaching the phone how to see."
With an iPad 2 or a smartphone, you can upload an overlay of your own information about a favorite object or landmark, joining hundreds of others at that location.
"It's very simple to just make your own," says Lord.
You use an app called Junaio -- a free download on the Apple App Store and Android Market.
As more users add such visual channels to an object, it becomes part of an augmented social network.