Best use of a QR code
This is the best use of a QR code I’ve ever seen. As you can see from the image below, you can only see the QR code on the glass when there is a dark beer (like Guinness) in the bottle.
I also think they didn’t care about versions. Doing a QR code means testing it on platforms with various operating systems. For example, someone with a first generation iPhone might not be able to use your QR code. Or the blackberry. Or the newest driod. And when the QR code does all the things in the example above, versions get even tougher.
My advice: chase the early adopters. They are the ones who will spread your news.