Facebook lets you download a ZIP file with all of your data—in theory. Turns out a lot of information isn’t included.

Here’s Nitasha Tiku, writing for Wired:

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

RELATED: Ever Wonder How Much Facebook Knows About You? Here’s How to See

A lot of people have downloaded their ZIP file only to be shocked at how extensive it is—the Facebook Android app was logging who people called and texted, for example.

Creepy as it is, though, this is just the tip of the iceberg, because the ZIP file doesn’t reveal anything about the hidden user data that enables targeted ads. This is understandable on one level: Facebook’s entire business model rests on serving up targeted ads better than anyone else, and revealing too much about how that works would compromise that advantage. But users are left seeing only a fraction of the information Facebook has on them.