About once a week I receive a manuscript submission or proposal in which I ask myself the question: "Why should this be a book?" Sometimes the question reflects the thinness of the material, or the suspicion that while somebody might be willing to read about the ideas contained in the proposal in a three-dollar magazine, or on a blog, they won't be interested enough to shell out fifteen dollars for a book.
At other times, however, the question reflects the static nature of the printed word versus the dynamic nature of the Web. This contrast is especially the case with books with a high image-to-word ratio—such as works by photographers or graphic designers or even architects. And it's also true of compendia—dictionaries, concordances, and reference works of all kinds. The Web allows animation, audio, innumerable illustrations, close-ups, downloads, hyperlinks, and all manner of interactivity that a book cannot. Many more individuals are likely to view a website of photographs than will ever come across, let alone purchase, the book form. The best thing about the Web is that it's in your power to make sure your site is never out of date: you can always revise information, add more photos or links or materials, and expand what's on it exponentially for relatively little cost. No need to wait for a book to be published or a new printing.
My advice then is for those who have an idea for a photography book? Get a really good website together (Canadian photographer Jo-Anne McCarthur's "We Animals"
is an exemplary one) and take the time to display your wares in as compelling a way as possible. But you may find that the material you present on line is more fully realized as a slideshow (with audio commentary) or one or a series of YouTube videos, or a combination of both? If what is presented is compelling enough to enough people then the book can come later.