https://www.theverge.com/2018/4/2/17188422/facebook-force-advertisers-prove-user-consent

Facebook has been rolling out a series of changes to its platform that are all aimed at closing up loopholes following the Cambridge Analytica data breach. Now, the social media giant will be launching a certification tool that will check and ensure that marketers are only sending ads to email addresses that were rightfully obtained with user consent.

The tool is called the Custom Audiences certification tool. A Facebook rep wrote about the tool to a marketing client in a message spotted by TechCrunch. They wrote, “Advertisers will be required to represent and warrant that proper user consent has been obtained for the use of any data uploaded.”