A QR Code (Quick Response Code) is a two-dimensional matrix barcode consisting of blacks modules arranged in a square pattern. It is used to store information that is generally intended to be read by the latest generation of mobile phones, smartphones and tablets.
It is a square abstract, which in reality may contain valuable information, including web addresses.
The "square" may contain information of any kind, within one cryptogram can be stored just over 4000 alphanumeric characters, then good to contain all the Web address of a site.
How to read QR codes?
Now all phones with an integrated camera can read these images simply by installing a software.
Some examples of freeware software for the QR Code letters:
How does this work?
First you must install on your mobile phone / smartphone / tablet a program that will decode the QR code or a QR Reader (usually found free on the net). Once installed you launch the application, then you must place the camera on your device the QR Code and you can immediately view the associated content.