@nony - Microsoft Tag reader is an awesome application. There are others like it that work well too, but I am familiar with this one.
It scans tag information that is encoded onto product barcodes. In the process it can download information about the product to your smart phone.
It opens up a world of possibilities, because there is virtually no limit to the amount of information you can download, although from a practical perspective you will probably want to keep it fairly tight.
A manufacturer can for example have a barcode tag on a wine bottle and the tag reader will scan it, and instantly they will see a multimedia presentation on their mobile phone about how wonderful this wine is, or whatever.
I think marketers are seeing a lot of possibilities with tag technology because it gives them additional leverage in enhancing the sales experience for the customer.