QR Codes

Ok. Just started thinking about this new type of barcode.

As far as I can see a QR code, hopefully as seen in the image with this post, contains information which can be input into a mobile phone, by taking a scan of it. The QR Code can be scanned if it is printed on paper or even scanned if on screen. I use an iPhone and a super scanner app called Qrafter.
But how can this be useful in education? In secondary and primary schools?