Amazon only sort of beat Google to this one.
Several months back (more than a year?) Amazon released a "search inside the book" feature to their web site. It's a handy gizmo to find more than just books with your search terms in their title or keywords. I don't know that it's sold many more books, but it definitely was a step in the right direction for what is known as "digital convergence" (bringing analog life together with digital).
While search for "John Piper" just now, the first entry I got back was title "Book results for john piper." Turns out, Google was only a few steps behind Amazon. They now have Google Print.
You guessed it, Google is now one step closer to fulfilling their mission of organizing the worlds information.