Microsoft has introduced a technology that competes with the QR codes. One of the main differences in the Microsoft Tag is that there is a tracking mechanism that will tell the tag owner how many people have accessed the tag… and also allows the tag owner to change the contents of the tag over time. QR tags are static.
All the tagging technology (readers, creators and the web site to control the content) are free at this time from Microsoft. [more]
Here are a couple articles of interest: