I have a personal Instagram account which I barely use (only follow a few people). I recently created a new test account with a separate e-mail address, logged out of my personal account, and added my new test account to the app on my phone, thus linking my number.

I figured Instagram would now know who I was due to device fingerprinting, but I did not allow them to access my contacts nor did my original account have much information about me or was linked to any other of my online accounts. My device was also only 6 months old.

I expected some information to be known but after logging in I found recommendations of people I haven't interacted with (face-to-face or online) in over 10 years, like my high school friend's mother and more recommendations that completely surprised (scared) me.

What techniques are generally used to find such data and how did Instagram potentially find out all that information about me?

  • did you link your first account to your phone (use the app on your phone with the first account)?
    – schroeder
    Commented Jun 9, 2017 at 6:55
  • 1
    I think this question covers yours: security.stackexchange.com/questions/61412/…
    – schroeder
    Commented Jun 9, 2017 at 6:56
  • @schroeder Yes it does! Seems like I over complicated things. Facebook owns Instagram so they must have linked my registered phone number to the one on my Facebook account and grabbed the friends list from there. Which would explain how they recommended people associated to my Facebook friend's network graphs, and not just my friends. Thank you
    – Mirodinho
    Commented Jun 9, 2017 at 7:38


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