Do come and see this idea for real at Derby Museums on April 9th. (search for GLAM and Derby) The work described here arose out out of a Wikipedia / Museum collaboration at Derby. Terence may have done better things but I think this is the coolest thing Ive been involved with. Its so simple and it works. Bluetooth and Geotags tell you approximately where a person is, but QR code tells you what they are looking at.