By cakmpls's definition, related to communication, no. By my definition, which includes changing the way you look at the world, yes. Is it art if only the creator sees it and is moved? If Picasso painted a masterpiece and his studio burned to the ground before he had a chance it to show anyone, was it still art? If someone makes a movie with a specific vision but it's taken out of their hands and edited into something completely different, which is the art?
Not all dreams change people, but many dreams have powerful effects on a life. Is it art? If not, what is it?