Here's a slideshow I put together earlier this year about the very basics of QR Codes.
Practical Uses for QR CodesSince then, I've been taking photographs of QR codes I've been seeing (everywhere) and then a screenshot of the destination of those codes. I've been shocked at how few lead to mobile-ready sites and even fewer leading to smarter content delivery or data capture.
As Chris Brogan mentions in his post Mobile Marketing Isn't a QR Code, "if you deliver someone to a page that requires they squint, scroll, and otherwise manipulate content in an uncomfortable way," that's not a good first impression. Slapping a QR code onto something doesn't make it useful to your business - or to your current or potential customers.
I'm compiling another slideshow demonstrating the good, the bad and the ugly about QR codes. If you have any examples that you've seen or that you want to share, let me know.