It is a QR Code, a type of two dimensional bar code, which I heard described as a cross between a chess board and a crossword. on a recent BBC digital planet podcast. The really great thing about them, and why I bothered to blog about them, is that most new mobile phones, well the ones with cameras and web access, can probably already scan them and use them for instance connect to a web address.
Thats exactly what this one does, it is the URL (web address) of this blog, just point your cameraphone at the image, on the screen! and take a picture. The next step depends on your phone, (HINT: you may need to read its instructions), activate the QR CODE READER option and you will get taken to your phone's web browser and directly to this very blog site! On your phone, no difficult thumb and finger typing required!
If your phone doesn't have a QR Reader built in (most phones less that 2 years old will have it), but a camera you can download the free KAYWA Reader into your phone.
If you want to create QR Codes of your own, snapmaze is a simple on-line application. Not only web URLs can be encoded, simple text, addresses and contact details, the applications are pretty endless. The QR stands for quick response, and the process of linking directly to the web on your phone is now very popular in japan and has become know as hardlinking, or physical world hyperlinks.