E-readers will soon be commodities, with low margins and standard feature sets. Kindle, Nook, or whatever - e-book readers will compete on price (and they will be cheap). The value-add for Amazon, BN, (or maybe Google or Apple) will be driving book sales.
A recommendation engine can do this to some extent ("Customers Who Bought This Item Also Bought"), but algorithmically based recommendations will never be as persuasive as an editorial review.
How do you decide what book to read next?
I always go first to nytimes.com/books  . A good review attached to a subject that I'm interested in, or an author that I like, will almost always result in a purchase (as an Amazon Audible audiobook or a Kindle e-book). A middling or bad review - no sale.
Sometimes I'll do a Google search for "book review (book title)" - and read reviews from other sites - but rarely. If the book is reviewed on IHE, then I'm definitely buying.
This book selection process has been seriously disrupted by the NYTimes paywall. Sure, it is easy to get around (just do a Google search with the headline of the article you want to read) - but this is an extra and unpleasant step.
Furthermore, my NYTimes reading had migrated almost exclusively to mobile devices (iPhone and iPad). Now I'm cut off. Perhaps I should subscribe, but I'm still annoyed that the NYTimes does not deliver to my home address (zip 03750), and therefore I can't get the paper+digital deal.
At some point, the big e-book platform providers (Amazon, BN and next Google and Apple) will understand the opportunity that the NYTimes has provided. How expensive would it be for Amazon to create a rich and deep selection of independent book reviews on the site? They have a good start with the Omnivoracious  blog and all the customer reviews, so scaling up to NYTimes quality reviewers should not be all that difficult (so he says naively).
Rich, independent, and challenging editorial content on Amazon could also capture writing and discussions about the changing nature of books and reading. Our community loves to debate the merits and dis-merits of e-books, different e-book readers, audiobooks, etc. etc. Provide a space for quality (paid) editorial content about books, the book publishing industry, and reading technology.
The key will be a willingness to spend money paying for high caliber editors and professional reviewers, and then to create a firewall to protect this editorial content from any sales considerations.
How much would it cost to re-create a NYTimes Book review like site for the digital age?
Which digital bookseller will rise to this opportunity?
Can this argument be applied to other markets?