QR Codes are 2-d pictures that link to BBM groups, web sites, etc. It started as an advertising medium in Asia and is spreading to Europe and North America now. In Japan the codes would appear on billboards, in magazines, etc, and you could get advanced word of a new product or even a discount if you scanned the code with your mobile.
I pitched an ad campaign to Nokia years ago with QR Codes as a cornerstone of the program. Unfortunately they had already decided to kill their North American presence and politely showed me the door.