Facebook claims users can view the personal information they have collected about you. But the download doesn’t include everything Facebook knows about you.

Nitasha Tiku, Wired:

“Download Your Data” hardly tells you everythingFacebook knows about you. Among the information not included:

  •  information Facebook collects about your browsing history
  • information Facebook collects about the apps you visit and your activity within those apps
  • the advertisers who uploaded your contact information to Facebook more than two months earlier
  • ads that you interacted with more than two months prior

Download Your Data is particularly spotty when it comes to the information Facebook taps to display ads. Typically, Facebook uses information it collects or buys to place users into categories that advertisers can target. This can include data a user provides explicitly (your age), implicitly (which browser you use) or unknowingly (information on purchases from loyalty cards).