system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does a company want to sell my personal info? To whom? For how much? What's the data even look like?

I keep reading that companies like Facebook, Google, and so many others like to collect our personal information to sell it. But to whom? What's that information even look like? Is it an Excel document that has my name and some columns with checkmarks confirming I watch porn and love video games? Who would buy that data and how much do they spend on it? How would they then use that data once they have it?
gpt
So the big common misunderstanding is that Facebook, Google, and most large companies **don't** actually sell your personal information. Yes they collect it, but they don't sell it. Smaller and more unscrupulous companies will sell your data though, usually to email spammers.

The big guys instead collect it, research it, and both share the results of that research and use that research to build more targeted ads.

If some random company is like "I have a product for cat lovers, I'd love to buy some ads on facebook in front of people who like cats" Facebook can not only make *exactly that* happen for that company, they can also tell things like "people over 40 are more likely to click on these links" "surfers are more likely to click on these links" and stuff like that. So now you can put your ads for cat products in front of surfers too, since you know they're more likely to buy it than other demographics.

Knowing *what kind of person* wnats to buy your stuff is extremely important, because it lets you put the ads or the product right in front of the kind of people who are most likely to be your customers.