The above picture is a QR Code or a two-dimensional bar code. The "QR" is derived from "Quick Response", as the creator intended the code to allow its contents to be decoded at high speed.
These types of code, which were initially used in manufacturing, are now used in a much broader context. QR Codes storing addresses and URLs may appear in magazines, on signs, buses, business cards or just about any object that users might need information about.
Users with a camera phone equipped with the correct reader software can scan the image of the QR Code causing the phone's browser to launch and redirect to the programmed URL. More information on QR codes is available on Wikipedia
If your phone does not possess a QR reader then we suggest downloading reader kaywa, though there are numerous other readers available on the web
Download our step-by-step guide to using QR codes here