My wife is a cookbook author and gets occasional fan mail. She loves hearing from people. A few weeks ago a librarian from an elementary school asked for our address because a little girl wanted to send her a letter. Apparently this girl kept checking out one of my wife's books over and over and loved it. My wife responded by sending this girl's class a full set of her signed books. So, worst case you get ignored, but most authors really like it unless they are super famous and inundated.