They obviously exchange (precisely targeted) attention for money: https://www.facebook.com/adsmanager/creation https://www.facebook.com/adsmanager/creation And

They obviously exchange (precisely targeted) attention for money: https://www.facebook.com/adsmanager/creation https://www.facebook.com/adsmanager/creation And they obviously give away some data for free, especially pertaining to users who click through OAuth consent screens as in the Cambridge Analytica case: https://developers.facebook.com/docs/graph-api https://developers.facebook.com/docs/graph-api What are some examples of transactions where they exchanged data for money?