I haven't seen this mentioned anywhere else. It would appear that the mobile version of YouTube now includes links to QR codes, so you can share the video with your friends. I've only seen this using the Android browser, I'm not sure if it's available on other devices.
Browsing http://m.youtube.com/ at the bottom is a new link
Clicking on it takes you to a QR code
It's using the Google Chart API to generate the code.
Will this spur QR codes into the mainstream? I hope so!