It is extensive.
The one with the cows looks like the most ridiculous, but the news video says it's actually been a big success for the farm. I guess one key is that the code is a social object more than just a link to an ad.
I think my favorites are the small ones on moving vehicles, and the commentary is perfect.
On of the problems with QR codes is the friction to acquire it, and the reward, usually some marketing gimmick. Hence the linked blog's derision. I did love the one with the code broken across several screens, all I could think of was "must...use...error...correction."
But I think if better implemented, QR codes would be an interesting stepping stone to augmented reality. One way to reduce the friction would be to make acquisition more automatic. For example, if you wake up your device and it detects a QR code in the camera's field-of-view, it displays the URL and a link to click.
As long as we're talking about AR, I'd rather the QR code be a link to some sort of format describing an object to display.
Example: you're walking by a movie theatre, wearing your super-hip AR googles that allow an overlay to be displayed. They detect a QR code on a movie poster for Jaws 17: The Jawing, and display a gigantic shark biting your head off, a la Back to the Future II.
Better example: Tubgirl. Tubgirl, everywhere.
... For example, if you wake up your device and it detects a human readable URL in the camera's field-of-view, it displays the URL and a link to click.
While at a gig the other night (at http://www.thefleece.co.uk), in between acts they had a projector above the bar displaying upcoming gigs on one side, and a music video, and footage from the ISS looping on the other. Next to the footage they had a QR code, pointing at the source of the video which I thought was quite good.
Also, it gave me something to look at between bands.