Privacy International did a piece on this kind of ad-tech data survaillance and they were saying "Here is the shocking details what an ad-company knew about me when I asked them to share everything with me in line with GDPR"
Then I emailed Privacy International, asking: How did they even knew your real name?
To which they replied "Oh, yes, we forgot to add that to the article, I actually gave them my name and my cookies, so they could tie all their cookie IDs to my name"
PI promised to add this "small detail" to the article. They never did: https://privacyinternational.org/long-read/2433/i-asked-onli...
They also promised to write an article about the implications of pseudonymous data and the possible link to real identities, which they also never did.