Facebook and Google Sell Your Data

By Chris Hoofnagle

Posted on March 29, 2018


It’s time to stop believing Facebook and Google’s propaganda.


Facebook and Google sell your data.


They sell it in a way that is difficult to understand, unless one works with APIs, or develops extensions and applications on their platforms.


Facebook and Google compete in multi-sided markets to become platforms. To do so, Facebook and Google must attract users, advertisers, and developers to their platforms. Facebook and Google connect users’ eyeballs to advertisers—that is the transaction that Facebook and Google want you to focus on. And that is the transaction where Facebook and Google offer attention and persuasion, which are problematic in themselves, rather than sell your data.


The developer-platform transaction is the important one, the relationship where Facebook and Google sell your data. In my Privacy & Security Lab at Berkeley, I show students how to use APIs. One lesson emerging from this lab is that developers often get more data than web users. And this is the way Facebook and Google sell your data: Facebook and Google reward developers for working on their platform by making personal data available—often much more data than are needed for API, extension, or application functionality. When Facebook and Google make your data available to developers, it is a transfer of value. Developers want access to personal data, and Facebook and Google gain the network effects and other benefits from a larger developer network.


The developer relationship is not understood by users, but highly prized by platforms. As Katherine Losse explained in The Boy Kings, Zuckerberg treated developers as trusted insiders, courting them with parties and “look[ing] away from the fact that almost all of Facebook users’ data was available to them through the platform.” The incentive structure also explains why, as Ezrachi and Stucke detail, Google bounced the privacy-preserving Disconnect from its app store while allowing data-sucking apps such as “Brightest Flashlight.”


Data business models are inscrutable to most consumers, and it is easy to mislead the public about data practices because they are hidden, often protected by NDAs. Information-intensive companies can look you in the eye and tell you something truthful that is entirely misleading. It’s time to wise up to one of the most misleading claims of Facebook and Google. Contrary to what they say, Facebook and Google sell your data.