Facebook is a social networking site where users can post pictures of their lives. When someone clicks on a picture, the user’s computer sends a request to Facebook for that person’s permission to share the picture with their friends. If the person agrees, then Facebook posts the picture to their friends and also sends an email notification to the user about how many people have seen the picture. If the person doesn’t agree to share the picture with their friends, then Facebook deletes it from their account.
