A QR Code is a matrix barcode (or two-dimensional code), readable by QR scanners,
mobile phones with a camera, and smartphones. The code consists of black modules
arranged in a square pattern on white background. The information encoded can be
text, URL or other data. - from Wikipedia.
During a time we've implemented a lot of tools and useful instruments for creating and using QR codes. So this page summarizes our efforts and contains a useful how-to guide.
How to do (with QR codes):