QR codes have yet to conquer the US and Europe but are prevalent in mobile phone-crazy Japan. Denso Wave, a Tokyo-based tech company, invented the nifty little two-dimensional bar codes as early as 1994. And they are everywhere now in Nippon: magazines and newspapers, billboards, clothes, beer cans, maps, business cards, cigarette boxes etc. etc. Scanning the QR code you see above should lead you to www.crunchgear.com, for example.
And the Japanese now even use QR codes on graves, as shown in the video below. It may sound macabre at first but seems to be a way to let people close to the person in question interact with each other without hassles, i.e. in the form of a mini social network that you can access with your mobile phone.