Many people are still active on Facebook, Twitter and Instagram despite digital privacy concerns. But even if you set out to truly understand all the information tech companies have about you, it's close to impossible to get your hands on all of the data. Witness the plight of one American professor who's waging a multiyear legal battle against political data firm Cambridge Analytica, trying to see what it collected, bought and sold about him. It's a David and Goliath story, and in this case, David is David Carroll, a media design professor in New York. Marketplace’s Jed Kim talks about Carroll's quest with Issie Lapowsky, a senior writer at Wired.

Today's show is sponsored by Pitney Bowes and Indeed.