"It comes as no surprise to any Facebook user that the social network gathers a considerable amount of information based on their actions and interests. But according to a report from ProPublica, the world’s largest social network knows far more about its users than just what they do online.
What Facebook can’t glean from a user’s activity, it’s getting from third-party data brokers. ProPublica found the social network is purchasing additional information including personal income, where a person eats out and how many credit cards they keep.
That data all comes separate from the unique identifiers that Facebook generates for its users based on interests and online behavior. A separate investigation by ProPublica in which the publication asked users to report categories of interest Facebook assigned to them generated more than 52,000 attributes.
The data Facebook pays for from other brokers to round out user profiles isn’t disclosed by the company beyond a note that it gets information “from a few different sources.” Those sources, according to ProPublica, come from commercial data brokers who have access to information about people that isn’t linked directly to online behavior."
"When asked this week about the lack of disclosure, Facebook responded that it doesn’t tell users about the third-party data because it’s widely available and was not collected by Facebook.
Facebook has been working with data brokers since 2012 when it signed a deal with Datalogix. This prompted Chester, the privacy advocate at the Center for Digital Democracy, to file a complaint with the Federal Trade Commission alleging that Facebook had violated a consent decree with the agency on privacy issues. The FTC has never publicly responded to that complaint and Facebook subsequently signed deals with five other data brokers.
Oracle’s Datalogix provides about 350 types of data to Facebook."