The Google 6 billion: Find it and soon buy it

Google Inc. today announced it expanded the breadth of its web index to more than 6 billion items, including 4.28 billion web pages, 880 million images, 845 million Usenet messages, and a collection of book-related information pages.
A new test service, called Google Print, enables users to find book data, text, reviews and bibliographic information, as well as links to direct purchase this went live in December, but seems–along with images to be a focal point of the announcement.
The FAQ for the print beta says:
“Google’s mission is to provide access to all the world’s information and make it universally useful and accessible. It turns out that not all the world’s information is already on the Internet, so Google has been experimenting with a number of publishers to test their content online.
On Google Print pages, we provide links to some popular book sellers that may offer the full versions of these publications for sale. Book seller links are not paid for by those sites, nor does Google benefit if you make a purchase from one of these retailers. In addition, these pages show contextually-targeted AdWords ads that are served through the Google AdSense program.”

Okay, so you test out selling books direct from a search-based interface that creates a meta layer of info. SEARCH==>SAMPLE==>PURCHASE
Then you become a viral network of notes that converts searchers into purchases and ships them to their destination.
Hmmmn…See the example here.which indexes the ISBN number.
Books as the playground for commerce,.where have I heard that before?