https://www.theregister.co.uk/2018/02/19/facebooks_solution_election_ad_fraud_snail_mail_postcard/

In the face of increasing public pressure to address election fraud, Facebook has come up with a novel way to check who's buying advertising on its site – snail mail.

As the Zuckerborg's shine rapidly fades, and governments and users wake up to the effects it has had on society, the firm is engaged in a battle to prove it can tackle the problems it has, in part, created.