QR codes may be slow to catch on here in North America but they are, like so much other cellphone-based goodness, big in Japan. The latest to get in on the action is none other than McDonald's, which is now printing the newfangled barcode patterns on all its food packaging so you'll know exactly what you're eating (if you want to know, that is). To read the info, you simply scan the QR code with your cellphone camera, which should automagically recognize it and direct you to a mobile website with the lowdown on the contents of your McFood, including any potential allergy warnings. For the two people in Japan that don't have a camera-equipped cellphone, McDonald's is also printing conveniently short URLs for the corresponding mobile website. Of course, all this info only is really more of a curiosity, since you've likely already bought the food by the time you're snapping pics of it with your cameraphone.