Hello Luca
Too much. I alternate between xitter, lemmy and YouTube. Sometimes I leave YouTube on in the background while I alternate twitter and lemmy. It’s a problem.
From what I know having worked in adtech,
With the above, even without knowing your name (this can easily be determined) , they are able to know enough about you to determine the kind of person you are, with whom you interact, where you go, your political affiliations, job, salary estimate etc and sell it to advertisers. This is usually sold as “audiences” but given the tools provided to advertisers, it’s easy to create hyper targeted ads and recommendations (remember Cambridge Analytica).
We voluntarily give up a lot more information than we realise.
And remember, the smartest people on the planet work at these companies, so the above is nothing in comparison to what behemoths like Facebook, Google, Tencent, etc are capable of.
We do, we gain and then but lose them in the womb. They’re called volar pads