Any company can upload a list of email addresses to facebook and say they have a relationship with you and then facebook will allow that company to market you.

Any company can upload a list of email addresses to facebook and say they have a relationship with you and then facebook will allow that company to market you. Its obviously against ToS to go out and purchase a list of emails and upload it to facebook and show those people ads. But uh, facebook can't prevent that without killing the feature. So in this case its not facebook sharing data, but companies lying to facebook and facebook going along with it to get paid.