Just saying that it won't matter much if removed from the equation.
I mean, if something makes your life easier, you would be a fool to not use it. but that is like saying not having a ferrari prevents you from driving to the store.
With third party cookies this looks like (simplified MVP form):
1. When you visited shoes.example, it loaded a pixel from ads.example. That pixel automatically sent your ads.example cookie, and put you on a remarketing list.
2. When you visit news.example, it sent an ad request to ads.example, which also automatically sent your ads.example cookie. Now the ad tech vendor knows to include the ad from the shoe site because it recognizes the third-party cookie.
On the other hand, without third-party cookies or any replacement browser APIs, how do these identities get joined? Very occasionally someone will follow a link between a pair of sites, and then you can join first party identities, but you probably don't have a chain of identities that connects a news.example first-party identity to a shoes.example identity.
1. When you visit shoes.example, it has an iframe to show an ad from ads.example. This iframe runs some JS to compute a browser fingerprint and then nests an iframe to hxxps://ads.example/?target=shoes.example&client=$fingerprint . The ads.example server records that this fingerprint has visited shoes.example
2. When you visit news.example, it has an iframe to show an ad from ads.example. This iframe runs some JS to compute a browser fingerprint and then nests an iframe to hxxps://ads.example/?target=news.example&client=$fingerprint . The ads.example server recognizes the fingerprint, knows that the client visited shoes.example earlier, and returns a shoes ad.
I do agree this is possible to do with fingerprints, though (a) all the browsers are trying to prevent fingerprinting and (b) a reputable ad company would not use fingerprints for targeting. This is my understanding of why Google is putting so much effort into https://github.com/WICG/turtledove
(Still speaking only for myself)
cookie synch, It's a freaking industry standard. And you want us to believe google money cow will dry as soon as the effort they are leading goes live?
> you want us to believe google money cow will dry as soon as the effort they are leading goes live?
"we are confident that with continued iteration and feedback, privacy-preserving and open-standard mechanisms like the Privacy Sandbox can sustain a healthy, ad-supported web in a way that will render third-party cookies obsolete. Once these approaches have addressed the needs of users, publishers, and advertisers, and we have developed the tools to mitigate workarounds, we plan to phase out support for third-party cookies in Chrome. Our intention is to do this within two years." -- https://blog.chromium.org/2020/01/building-more-private-web-...
They are describing adding new capabilities to the browser that would make this possible, in a privacy preserving way. Ex, https://github.com/WICG/turtledove/blob/master/FLEDGE.md
(Still speaking only for myself)
google sends id abc to shoes.com and id xyz to news.com. both sends those ids back to google's own adserver. presto, google knows you are seeing those two ads.