A QR code (abbreviated with Quick Response Code) is the first matrix barcode (or two-dimensional code) for the automotive industry. Recently, the system has become popular outside the industry due to rapid readability and relatively large storage capacity. The code contains black modules that are arranged in a square pattern on a white background, encoded information can be done with any type of data (e.g., binary, alphanumeric or kanji symbols)

They come to us from Japan, where they are very common. The QR for quick response is low (they can be read quickly by a cell phone) They are used to take a piece of information from a transient media and put it in your cell phone. You can see the QR code on a billboard, web page or someone's T-shirt in the advertisement of the magazine once it is in your cell phone, it can give you information about that business (sub The Ogkrtaon allowing to discover nearby places), or T-shirt wearer details, which shows you a URL you can click to view the trailer. A movie, or it can give you a coupon that you can use in a local outlet. Why are they more useful than standard barcodes is that they can store more data (and digitally present) including URL link, geographic coordinates and text. Another important feature of the QR code is that many modern cell phones can scan them, instead of requiring a small hand holding scanner to scan them. The complete Wikipedia description is here