> Not true, FireFox and Safari have had them off by default for over a year now.

Not quite. They will block some 3rd party tracking cookies that fall on their tracking blacklist. If you want to block all 3rd party cookies you have to explicitly disable them.

Safari does actually block all third party cookies by default, not just a subset. And has been doing so for about a year now.

If I understand correctly, they allow 3rd-party cookies but delete them at the end of the browsing session rather than respecting the expiry.

Care to reach out? This username at Microsoft.

We're working to understand what legitimate use cases are broken without 3p cookies so we can work with Google to backfill them. FLOC helps ad trackers track but doesn't help with any of the legitimate uses of 3p cookies like auth.

Since you seem to work for Microsoft, the broken use case I know: without 3p cookies Microsoft Teams is broken (it shows a not very useful error page asking to refresh the page, when you do it shows the same error again). Many of us need it for remote work so I guess this one of the things Google had in mind when they delayed disabling 3p cookies by default.

Yes, Teams relies on silent auth from within an iframe (all those chat windows etc). This is impossible without 3p cookies, so we're working with Google to find a solution. Storage access API in Safari works, but sounds like it won't make it to Chrome.

Thanks, nice to know you are working on it.

Auth should be doable with just redirects though right? Isn't that how OAuth and OpenID connect work?

Same thought. I’m curious to know what other kinds of authentication protocols require third-party cookies to operate. Within OIDC, even more obscure/advanced features such as session management and global logout require only 1st party (the IdPs) cookies in order to function.

I guess the tradeoff being made here is just leaning into our reliance on the certificate authority system. Whereas before, with third party cookies, you might have had more flexibility with how you structure your domains.

The implicit grant, while deprecated, is still used across the ecosystem. Further, embedded apps (eg you have a portal that iframes Salesforce and Salesforce needs to be authenticated) can't redirect to the login page or open that iframe for cookies.

Front channel logout is also broken, part of the OIDC spec. It opens iframes to sites, but the sites don't get their cookies and can't write them.

OAuth sometimes is done using an iframe and a pop-up window instead of by navigating to the federated auth provider and back. That version often needs third party cookies.

Sure, I suppose all that (waves hand at third-party cookies situation) is what I meant by the long phase out of them. As far as I can recall those defaults were signaled a fair amount of time in advance.

I have sympathy for anybody with a legitimate use for third-party cookies whose life has been made more difficult by bad actors abusing features to maximise their own profits.

Same tragedy that finally caused origin-based cache partitioning at the expense of some performance.

this is the same execuse facebook's been using, although they're trying to push the narrative that limited tracking in Apple's iOs 14+ "hurts Small Business!"

https://twitter.com/jason_kint/status/1383391849902075911 (video in thread)