Facebook accounts are now being protected by a new email standard known as Require-Recipient-Valid-Since (RRVS), an extension for the Simple Mail Transfer Protocol used as a way of detecting changes to mailbox ownership and preventing email – such as account statements and password change requests – from being delivered to the wrong person.

The social media giant worked with Yahoo and came up with the method after Yahoo announced last year that logins would be made available if not used for a while, a Thursday post indicates.

“The enhancement inserts a timestamp within an email message to indicate when we last confirmed the ownership of a Yahoo account,” according to the post. “If the account changed hands since our last confirmation, Yahoo can just drop the message, preventing delivery of sensitive messages to the wrong hands.”