Some people think the big tech companies literally sell your data though, so IMO it’s important to clarify.
There are companies that do that though, like Acxiom, LiveRamp, CoreLogic, etc. With Acxiom at least, you can buy lists like “high net worth individuals who are likely to buy a new car in the next 6 months” and get a list of names, phone numbers, and email addresses, based on data they’ve collected from both public and private sources.
Those data broker companies collect data from things like supermarket loyalty programs (to determine consumer spending patterns) and other companies who are willing to sell data about you, and compile them into profiles.
This is awesome!