Email lists are used to create Facebook ad audiences.
How does it work? We provide Facebook with a list of emails in CSV form. Because most Facebook users have a registered email address with the platform, Facebook can match the details provided to a user on the platform and re-target dark posts towards them. Facebook anonymizes the data, so personal information is protected.
We can also use this data to build audiences like your email list, which can expand the target audience in a very qualified way.