About the only experience I've directly had with tags has been to insert tags for Google Analytics in a couple of blogs. However, Pierre's piece piqued my curiosity so I did a bit of research to learn more about tags.
I found Ingrid Lindgren's writeup in TechCrunch about tags and Google Tag Manager particularly enlightening:
Hi Pierre, I've no reason to play around with Tag Manager as I'm not a digital marketer, but I do wonder whether this new product allows for deeper or easier analytics of the tag effectiveness -- or is it just ease of viewing and managing the tags through the GA dashboard that's the benefit?
It may be impossible to predict the perfect bracket, but these academics have managed to predict perfectly the "at large" bids that were included in the March Madness NCAA college basketball tournament this year and with 96% accuracy over the last 6 years.