QR codes are a technology that desperately wants our attention. They appear everywhere from supermarket shelves and magazines to hiking trails and tombstones. Never heard of a QR code? You're looking at one right now. Scan the image at the top of this article, and it'll open a link to the mobile version...of this article. Very meta.
That's a pretty typical example of a QR code—occasionally useful, but often pointless. Either way, these plucky information sources are routinely ignored, and usually reviled. Here's where the next big thing in scannable coding went so horribly wrong.