It seems that as soon as Facebook digs themselves out of one privacy scandal, they find themselves embroiled in another. This time this scandal comes in the form of shadow contact information, which according to a report from Gizmodo who worked with computer science professor Alan Mislove managed to uncover.
Ikn their report, they found that advertisers were able to target users based on information that is not public. This might be information that you’ve shared with Facebook for security purposes, like a phone number you can be reached to recover your account, and so on. Gizmodo and Mislove tested this theory in which the former bought an ad targeted at Mislove and gave them a landline number for Mislove’s office, a number which he had never provided to Facebook, but yet within an hour he saw the ad anyway.
Gizmodo’s Kashmir Hill did ask Facebook’s PR team about whether they use shadow contact information for ads last year, in which they denied doing so, but this seems to prove otherwise. This isn’t just a one-off fluke because a bunch of other researchers conducted similar tests and found similar results.
Mislove said, “I think that many users don’t fully understand how ad targeting works today: that advertisers can literally specify exactly which users should see their ads by uploading the users’ email addresses, phone numbers, names+dates of birth, etc.” In the meantime for those who want to learn more about the findings by the researchers, head on over to Mislove’s website for the details.