By clicking the button, a screen will open up and will then prompt the user to enter the mailing address of a person as well as an option to write down a personal message to be included in the photo (see example above). Few testers say that for now, they were only able to mail their own private photos, and that it doesn’t work on public photos. The new “Mail A Postcard” feature is reportedly powered by Sincerely, the makers of Postagram. Details of the feature are still bleak, and Facebook has yet to release an official statement to confirm it.