Bookish.com will launch later this summer. Hachette, Simon & Schuster, and Penguin partnered to found the site, with AOL providing advertising. But it is a publisher neutral site - in six months, nobody at Hachette, Simon & Schuster, or Penguin will be involved. The site will also launch with books from all publishers.
Bookish is a response to the problem of discovery. With many bookstores closing or devoting floor space to ereaders, it has become harder to find new books. Bookish's central feature is a recommendation engine based on factors like content and writing style. (In contrast, Amazon's engine is based on what other people purchase.) While books will be sold on Bookish, it is not an attempt for publishers to become booksellers.
Bookish will also contain Q&A's, book trailers, and other multimedia content.
I've heard mixed thoughts on the site, but I think it will be well worth checking out. You can go there now and sign up to be notified when the site launches.