Facebook Is Giving Advertisers Access to Your Shadow Contact Information

Facebook is not content to use the contact information you willingly put into your Facebook profile for advertising. It is also using contact information you handed over for security purposes and contact information you didn’t hand over at all, but that was collected from other people’s contact books, a hidden layer of details Facebook has about you. The junk email address that you hand over for discounts or for shady online shopping is likely associated with your account and being used to target you with ads. And users who want their accounts to be more secure are forced to make a privacy trade-off and allow advertisers to more easily find them on the social network.

Source: Facebook Is Giving Advertisers Access to Your Shadow Contact Information