A great collection of the DO NOTs of QR code use. WTF QR Codes.
Developers: create an app icon card and leave an impression with the app2card service.
I am not affiliated with the service.
TagMyDoc – Creates a QR code to a copy ‘in the cloud’, of your document.
Considering the service is still in beta, they obviously have high ambitions as there is Office add-ins, iOS, Blackberry and Android apps marked as coming soon.
I am not affiliated with TagMyDoc.