'You! hypocrite lecteur! — mon semblable, — mon frère!'(TS Eliot, The Waste Land, busily misquoting Baudelaire's Au Lecteur)
The thing about readers is, that once the author or artist has published, the readers continue to form the work of art. It becomes a collaboration between the artist and the reader/viewer. The reader/viewer interprets it in a new way, reading symbols into it that weren't necessarily intended. It's like an alethiometer. Whether or not this is a good thing depends on the ability of the readers to transmute it in their own athanor into some glorious new thing, or to drag it down into the mire.
A wonderful book which explores the relationship between the author and the reader (in this case, a mutual relationship) is Hallucinating Foucault by Patricia Duncker. It's the only book I've ever read where I got to the end and wanted to read it again.
And there's an interesting spin-off post from Ulysses Chang about the creation of virtual worlds.