I like that Magic Hat gave mobile engagement a try here. Their younger audience definitely might have a higher likelihood to know what a QR code is and have a smartphone to use it. However, not everyone would recognize it especially hidden in the label. The fans of the brand that did engage seemed willing to give their glowing opinions of the beer.
Although there is some debate about whether QR codes are just a fad, I like the fact that companies and brands are experimenting with it and even having fun with it. It would be all too easy to put a website url on a beer bottle label. Consumers would more likely have their phones within reach and scan the code than go to a computer to visit the site.
We need more creative applications of mobile interaction and I'm glad I happened to see this one!