[Erwin]

I wonder if there's a way to generalize this so any text or image can have metadata about purchasing the exact product. Something like a shorter UPC but with a non-intrusive reader embedded everywhere offering you to buy the product through manufacturer-controlled channels (varying depending on what country you are in).

You "just" need to get enough users to install the scanning software; maybe the next iPhone will come with Apple Shopping that scans all text you see and all images for the metadata/watermarks. As it detected a product, the new second $ button lights up. Press down on it for a second, and the product information pops up (Apple Shopping knows your size/address/credit card already of course). Hold it down for a few seconds longer, and you've made your purchase. Don't, and a few weeks later maybe the seller gets to send you a 10% off coupon.

Actually, Amazon's phones might already have something like that, letting you scan a bar code in a physical shop but purchase from Amazon.

[pjc50]

Isn't this effectively the failed cuecat model?