Most of the time people put a URL as the QR code so they have records of when it’s scanned. I even heard of one firm where the staff had a competition to see who could get their QR code scanned the most.
But the problem with that is that firstly it doesn’t work if the user is off line, and secondly, you make the user perform an extra action to get to anything good.
What’s the alternative? You can embed several pieces of information including a URL in one code with a contact record (VCARD).
This is what comes up when you scan the QR code on my business card:
The user is instantly presented with options to email, call or visit my website – not to mention saving the whole lot to their phone book for later use.
I just wanted to briefly mention this as today someone said it was the first good use of a QR code they had seen. See this? This is my smug face.