Quote from the movie Garfield: "Got milk?"
Advertisement is all about getting your message across. The easiest way to make a message more appealing is to use graphics.
QR Codes can accomplished a multiple task in your advertisements.
Its main usage is to provide a fast and easy way to link your advertisement to the internet by using the qr code as a printed hyperlink, the call to action in your advertisement.
Since the QR code itself is also a graphic, with some alteration its graphical appeal can be made to match the remainder of the advertisement, even containing a visual message of its own.
The third task of the code is to measure the advertisement effectiveness by measuring the amount of scans, locations, time, type of mobile device used, etc,