“Many people I’ve spoken to have a pretty good understanding that companies like Facebook and Google have a massive amount of data on them. And most of those people also understand that companies like Facebook and Google package this data about them and sell it to advertisers. But few people I’ve talked to know that Facebook, Google, and other companies also sell your data to third-party data brokers.
As the name suggests, a data broker trades in information—your information. After the data broker buys information about you from Facebook or Google, it then in turns sells your information to other parties: businesses, advertisers, governments, consulting firms, bounty hunters — you name it. They can see where you live, what you search for, who you like, who you love, what your religious and political beliefs are. And those parties can use your information pretty much however they want — and you’ll never have a clue they are doing it, nor will you be compensated for them using your data or be able to tell them to stop using it.”
quote article below:
https://medium.com/fast-company/tim-cook-its-time-for-the-shadowy-world-of-data-brokers-to-end-b0ecf243f82d