My company went to a trade show recently, and instead of brochures, we made up a little business card with some summary information on the front, and a big QR code on the back. When you scan the QR code, it puts the summary and contact information into your phone as a contact. (It's labeled, so people know that scanning the code will transfer the card's information to their phone's contact list). I think this is pretty darn useful. It's nice to have something physical to hand to someone, but nobody wants to re-key contact info. And we want to make it easy to get the info from the card into their phone. You can use vcard or MECARD format. http://code.google.com/p/zxing/wiki/BarcodeContents

I don't know why more people don't use the scan-to-transfer aspect of QR codes.