I may be old school here but these things give me the willies.   Its one thing to buy something at a store and they scan the item at the register (you are in fact getting a tangible item)  but these QR codes on websites are not the same.

Unless you have an iphone and can read these things, there is no telling what they say, they could be promoting some other site or even saying "your breath smells like poo"  who knows!   And these companies that issue these QR's think that i am going to put something that i have no idea what it means on my website, i think not.

Maybe this is the new wave of the world, i guess its the new craze. But to me its just something else that can be exploited to the point that noone really knows what is behind the hidden code even if you can read it with your phone. 

I dont see this as an innocent tool, i see this as the next generation of exploitable items to make somone else rich while they laugh all the way to the bank.