The nice thing about one-way functions is that they let you make abstract claims about messages without actually revealing the messages themselves. For example, suppose that Alice has written the greatest haiku ever. Understandably, she is protective of her work and does not want anyone else claiming false credit for it (and Mallory surely would do so to promote his own reputation as a poet). Unfortunately, Alice's publisher is taking a while to decide on the right typeset font. In the meantime, Alice can still do something to prove her claim to the material. She can run her haiku through a one-way function (after all, to the computer it is just a big binary number) and publish the result in the New York Times' personal ads. Should Mallory manage to somehow steal Alice's fine poem, Alice can still prove she had written it before the Times' publication date by running Mallory's stolen copy through the one-way function as a demonstration to the reading public.