Facebook allows advertisers to target you based on your hidden profile

So you have restricted the information that advertisers can see on your Facebook profile, but you still receive almost perfect ads? This could be due to your shadow profile.

At one point, you may have given your phone number to Facebook for a two-factor authentication or a friend may have sent your email address to the importer in order to find friends on the platform.

These phone numbers or emails may not be visible on the profile, but they are in a hidden layer called shadow profile.

Advertisers can use this hidden layer of personal information to target you with ads, as reported in a Gizmodo report.

All advertisers need to download the phone numbers and email addresses that they have collected on Facebook. Most of us do not think about giving these details when you buy something from an online store, or you sign up for a political campaign.

Facebook calls this a personalized audience and allows advertisers to sell to people they already know that they are interested in their product or service.

What's troubling is that advertisers can target people who have provided their phone number to Facebook, thinking that this would only be used for security reasons, or did not know that their details were being divested.

A study cited by the report saw researchers at Northwestern University check whether Facebook was using parallel contact information by downloading hundreds of college landline numbers.

A landline number is information that will probably not be added to his profile, but that would probably remain inactive in his personal contacts, to be uploaded to Facebook by users looking for friends.

The study revealed that many of these numbers could be used for ad targeting, resulting in an advertisement in the news feed of one of the newspaper's researchers, Alan Mislove.

Facebook did not reject the findings of the study, with a spokesperson explaining via e-mail: "We use the information provided by users to deliver a more personalized Facebook experience, including ads . the contact information that users download or add to their own accounts. You can manage and delete the contact information you have downloaded at any time. "

What the report reveals is that Facebook may not be transparent enough when it comes to managing data that is not publicly available on your profile, resulting in almost psychic advertising and frightening suggestions.