It's called a QR code -- short for Quick Response. Smart Phones with cameras can download a special application. If you take a photo of the code, it will take you directly to the web page.
What it does for mailers is connect their printed mailed items to their online store.
It allows our customers to have both an online and a print catalog presence.
And, not to be left behind, here's the Your Postal Blog QR code.
If you have a smartphone, try it out! Care to comment?
What do you think?