[zymhan]

It's folly to think an account is the only way for advertisers and retailers to identify and track you.

Signing up for an account is just more explicitly forking over and sharing data. But you're being tracked by every possible method, and it is possible to piece together the remaining information.

[user17843]

Where is your evidence?

Did you even read my comment? The typical pihole lists already include tracking domains.

What you imply is that if I visit youtube.com with tracking disabled, they still create a profile of me. Then tell me, what unique identifier do they use?

[dmitriid]

Browser fingerprint, referrers, available cookies, IP address immediately come to mind.

[user17843]

OK, but how do you account for changing IP-Addresses? You would need to take one identifier that never changes.

Maybe they have machine learning which combines a couple of factors and then create long-term profiles based on the likelihood of some data belonging to the same person.

That would be illegal though.

[dmitriid]

That’s what shadow profiles are: they are not necessarily illegal (depends on jurisdiction, illegal under GDPR), they act on probabilities (this particular set of data identifies a person and is significantly different from/similar to other sets of data), they look for patterns in data and behaviour (a user with browser fingerprint A from Pasadena that looks at youtube videos of category X yesterday and today is likely to be the same person even if IP changes)