And touts its new "mega e-bookstore" as the world's biggest, according to this NYT story. Good for publicity, not so good when 500K+ from the 700K titles are free, public domain (read: old) books. But still, in my opinion there's one key issue that makes B&N more palatable than arch-rival Amazon.com: B&N's e-books are available on existing, generic technology (hard and soft) that's long been in use by industry pioneers Fictionwise, recently acquired by B&N. From iPhones and Nokias to Macs and PC's, via any carrier or ISP in the world, you can easily get PDB-formatted e-books.
Not so with Amazon.com's proprietary Kindle technology that's become a media darling in the past months. But I predict Kindle's not going to succeed in the long run, at least as a piece of hardware. The reason is the lack of a good answer to this question: "Why an extra dedicated device when my life can be easier with just a mobile and/or a laptop?" However, going proprietary has its attractiveness and B&N may well prepare a direct response to Kindle via the upcoming PlasticLogic technology.
Amazon.com has already covered the non-proprietary base too, with their generic platform e-bookstore, Mobipocket. But they never let revenue slip outta sight and think of putting ads in e-books, as per AdAge. To their credit, however, Amazon.com also did one very good thing, consumer-wise: pricing e-books lower than their printed counterparts. Sounds like a 'doh' gesture, but e-books have curiously been just as (if not more) expensive than books without any economic justification. That is, if you rule out greed and fear.
All in all, IMHO there's no clear leading brand in an emerging market that's still in its late infancy. But many heavyweights are already operating in it, which shows it has a bright future.
Disclosure: I'm a long-time reader of e-books. I've used Fictionwise's eReader.com for over five years.