While Amazon.com executives typically decline to comment directly about competitors, CEO Jeff Bezos had some distinctly negative things to say about Google's book-scanning project at the recent Wired conference in New York. Google in a blog post addressed Bezos' criticism, and today announced a series of upgrades to its Google Book Search function.

At the Wired Disruptive by Design conference Monday, Bezos, without getting into specifics, said Amazon has "strong opinions" about Google's settlement with authors and publishers to allow millions of books, many of them out of print, to be published and indexed online, and said the settlement should be "revisited." The settlement faces antitrust scrutiny.

Google, in a blog post, said Bezos' comments may be related to the search giant's recently revealed plans to allow publishers to sell electronic versions of newer books direct to consumers through Google. That kind of program would ratchet up competition with Amazon's Kindle e-book business, which puts a heavy emphasis on bestsellers and new releases.

"We can't presume to understand the full nature of Amazon's statements, but we believe they go to the heart of our continuing efforts to make books more available and were likely motivated by recent news about Google Books," blogged Google Books Engineering Director Dan Clancy.

Today Google launched a series of new features for Google Book Search, including a new toolbar option to embed previews or full views of scanned books.