4 ms·

I do not have the facebook app on my phone. I downloaded Instagram and it magically knew one of my email addresses (not the one used with my facebook account).

I do not have the facebook app on my phone. I downloaded Instagram and it magically knew one of my email addresses (not the one used with my facebook account). I deleted it, mashed the keyboard for the new email address, declined syncing contacts, blocked the permission as well as every other permission, and lo and behold it still shows all of my facebook friends on instagram as suggestions. Fucking creepy.

forgot-my-pw 9y ago
Even if Facebook doesn't get the data through you, it still gets your data from people you know.
- 0x00000000 9y ago
  It was people who don't have my phone number or any other information including people who I am not friends with and only messaged once from a buy/sell group. I am guessing because I used the app at some point on my phone it fingerprinted it, then Instagram goes and fingerprints it when you install and links your account even when you decline to do so.
  - nashashmi 9y ago
    Spammers get your email address the same way by hackers who hack your friends.
cdlvan 9y ago
If you previously had Facebook or Messenger installed on the phone it's possible they saved some user info on the device or in the cloud linked to your device ID.
- Im_Mr_Manager 9y ago
  AFAIK device uuid has been unique to device+app for at least 2 years now (iOS).
  - zer00eyz 9y ago
    device + app having a unique UUID has been going on longer than that. 3 years ago uber got popped for this: https://www.theverge.com/2017/4/23/15399438/apple-uber-app-store-fingerprint-program-tim-cook-travis-kalanick https://www.theverge.com/2017/4/23/15399438/apple-uber-app-s... I can tell you that fingerprinting is still possible today.
  - aplummer 9y ago
    It’s company not app on iOS, you get a new one if you delete every app from one publisher
dillondoyle 9y ago
Lots of ways this could happen but people often forget about GPS/location services which are very accurate. I'm not sure if you have never had FB app on your phone, but even if you never installed FB app on your phone there could still be geo-associations inferred. Think about the times your phone is near your friends phones, how your phone probably sits in the same space every night, the overlap between your IP location to whatever other devices connect behind your NAT which also send data to FB.

forgot-my-pw 9y ago

Even if Facebook doesn't get the data through you, it still gets your data from people you know.

0x00000000 9y ago
It was people who don't have my phone number or any other information including people who I am not friends with and only messaged once from a buy/sell group. I am guessing because I used the app at some point on my phone it fingerprinted it, then Instagram goes and fingerprints it when you install and links your account even when you decline to do so.
- nashashmi 9y ago
  Spammers get your email address the same way by hackers who hack your friends.

cdlvan 9y ago

If you previously had Facebook or Messenger installed on the phone it's possible they saved some user info on the device or in the cloud linked to your device ID.

Im_Mr_Manager 9y ago
AFAIK device uuid has been unique to device+app for at least 2 years now (iOS).
- zer00eyz 9y ago
  device + app having a unique UUID has been going on longer than that. 3 years ago uber got popped for this: https://www.theverge.com/2017/4/23/15399438/apple-uber-app-store-fingerprint-program-tim-cook-travis-kalanick https://www.theverge.com/2017/4/23/15399438/apple-uber-app-s... I can tell you that fingerprinting is still possible today.
- aplummer 9y ago
  It’s company not app on iOS, you get a new one if you delete every app from one publisher

dillondoyle 9y ago

Lots of ways this could happen but people often forget about GPS/location services which are very accurate. I'm not sure if you have never had FB app on your phone, but even if you never installed FB app on your phone there could still be geo-associations inferred. Think about the times your phone is near your friends phones, how your phone probably sits in the same space every night, the overlap between your IP location to whatever other devices connect behind your NAT which also send data to FB.