[carlosjobim]

You use promotional codes for attribution, then you have complete knowledge. So it's extremely easy, and a solved problem. No need for analytics, no need to infringe on privacy.

[plorkyeran]

I watch a youtube video and the youtuber shills me some product along with a promo code. A week later I decide to buy the product, but I don't remember what video had the ad or what the promo code was so I just don't bother with it. How are you going to attribute this sale to the youtuber?

[carlosjobim]

In those cases you can't attribute, but that's okay. With normal ads you have zero certainty of attribution.

[8note]

If you can figure out the attribution, I'd say you've infringed on privacy.

You know what the buyer was looking at

[carlosjobim]

That's not an infringement of privacy in any way. Likewise then you know what the buyer purchased, since you sold it to her.

And nobody is forced to use a discount code.