QR codes create a hyperlink between a picture in the real world and th eonline world -- this is called mobile tagging and the act of linking is called a hardlink.
QR Codes are a tool that is becoming used to link moble and handheld users with the web in a process that is called making a hardlink or mobile tagging.
Mr. Robbo, the PE Geek, filmed this video on his cell phone about how he uses QR Codes in the classroom. He filmed it on his cellphone and uploaded it to qik -- he is in Australia!