"What if every store had a bar code sticker on its window so that you could pull out your iPhone (Android) wave it in front of the bar code and get all sorts of information about that business—the telephone number, photos, customer reviews?"
It's just a way of encoding Web addresses.
You can make your own for free at places like QR Stuff and delivr. Also Kaywa lets you encode text, SMS, etc.
Here's one for Art Crimes: