Reuters first reported the postcard identification this week, and Facebook confirmed its plans to CNN Tech. When people create certain political ads, Facebook will send a postcard via U.S. mail to a physical address. Facebook has previously said that once ad buyers' identities are confirmed, all political ads on the site will contain a notice disclosing who paid for them. Facebook has previously said it hopes to launch its ad transparency efforts by this summer. A Facebook spokesperson would not say whether the security codes on postcards would be obfuscated or whether Facebook would allow them to be sent to post office boxes.

Source: CNN February 20, 2018 22:07 UTC