Just like Microsoft, Apple, or any company following the law. You see the trend here? The law.That is true, they don't sell you data. They give it to governments for free.
I know that, that's literally my job as I work in a big data context. What I was quoting, and refuting, was that google sold your personnal datas. Which is wrong, they just sell a channel to you, without knowing who advertisers sell to.Of course they do not sell their proprietary data. That would be selling the cow instead of the milk. They are the intermediary. But hey its not just Google. That is what your club cards are for too. These companies do reserve their right to sell their data [about you] to other entities. Read the fine print. And read the article linked previously about 23 and me.
They absolutely do collect a creepy amount of information tied to your real identity. Technically much of the information is stored in non-relational, big data, databases. The real technology in big data is the proprietary algorithms that can relate the information between identities and other data. Yes, they use it to sell profiles for marketing and other research in other spaces.
They can and do tie those advertising profiles back to a list of devices and real identities for targeted advertising. They route Hawaiian vacation ads to websites you happen to be visiting, after you browse an article about Hawaii, even on other devices.
If the general public ever saw what they could provide about an individual if they ever chose to, that would be their doom. But its all too abstract for most people to really care.
And the point is, "if they ever chose to". The army can also destroy your face, hell the closest fencing club can also poke people to death if they ever chose to.