[lxchase]

I can shed some light on this maybe, don't have a SO account. You're completely right about "SEEM". It does do enough that it significantly lowers the resolution of data and ability for systems to infer your behaviors / persona. It will force more of the ad ecosystem to server to server data pass through: https://developers.google.com/tag-platform/tag-manager/serve...

I mention it in a post above, but data brokers have existed for a decade, which don't really care about any of this. Your email/phone/credit card + purchase behavior for instance, is likely sent to 3rd parties (as md5/sha hashed values) It boils down to sample resolution and sample size. Javascript made it really easy for literally every website to collect browse behaviors. ITP makes the skill ceiling / investment to collect this data much higher.

[EGreg]

How would third parties track you across websites now? Given any skill level?

I can think of only one: convincing websites to add a CNAME to point subdomains to their servers.

[vladvasiliu]

I don't work in the ad space, but it's my understanding that that's where things are going.

See here for Facebook, but I'd expect other providers to do the same.

https://developers.facebook.com/docs/marketing-api/conversio...