he master switches also don't affect what third-party applications can do on your profile
but they don't affect what Facebook calls your "directory information," which includes rules about whether people can search for you, send you friend requests, or see your list of friends.
"The privacy page is dominated by three big master switches. The buttons are marked "Everyone," "Friends of Friends," and "Friends." Pressing one of those will decide most of your Facebook privacy settings in one go."