It's the right of the author own his or her own work and all copies that are made of it, in whatever form that might be. In short, what I write and create is my property, and mine alone.
Authors work hard to write what they do, whether it's a book or something on their webpage.
I think most people agree that the person who produces the work should own the work, unless he or she has agreed to sell it to a particular person or persons. For example, you have every right to buy my books, and after you do so, you have every right to fold, spindle, or mutilate them. Stealing is illegal. And publishers, especially big New York publishers, really, really hate it when someone else uses stuff without permission that the publisher has paid exclusive rights for. Think about the big music companies and what they have done to Napster.