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This article was published on September 28, 2018

Facebook advertisers can target you with data you didn’t even list on your profile

Facebook advertisers can target you with data you didn’t even list on your profile Image by: Anthony Quintano / Flickr

Facebook is sharing personally identifying information that you never submitted to the social network with its advertisers – and you can’t erase it from their records.

That’s from a paper (PDF) published by researchers at Northeastern University and Princeton University, who looked into how ad targeting works on Facebook.

Say you’ve got a mobile phone number and a landline, and you’ve listed only the former in your profile. If an advertiser has that number in their database, they can use it to target you with ads on Facebook. But if the advertiser has the landline number, they could target you with that as well.

How’s that possible, when you haven’t shared the landline number with Facebook? Well, you may not have given it to Facebook, but if you gave the number to a friend who’s also on the social network and has it saved in their address book (which Facebook has access to), then it can be associated with your profile.

As Gizmodo noted in its piece, Facebook has previously denied doing this. What’s more, if you give the site a mobile number solely for two-factor authentication, that can also be targeted by advertisers who have it listed in their database.

This isn’t the biggest infraction Facebook is guilty of, but it proves once again that the company doesn’t care about your privacy.

Here’s more damning context: WhatsApp co-founder Brian Acton – who sold the service to Facebook and resigned from the company last year – said that the company had plans to go against his vision and monetize the messaging service through advertising, even before the acquisition.

Facebook exec David Marcus, who formerly led Messenger and is now in charge of blockchain-based initiatives at the company, responded with a post in which he labeled Acton’s statements “a whole new standard of low-class.

Marcus added:

… Facebook is truly the only company that’s singularly about people. Not about selling devices. Not about delivering goods with less friction. Not about entertaining you. Not about helping you find information. Just about people.

I’ll leave it to analyst Ben Thompson to expertly sum up why Marcus is on the wrong side of this fight (captured in brief in the tweet below):

Gizmodo’s enlightening piece is worth a read; you may now delete your Facebook account.

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