The connection between search engine optimization (SEO) and Google's just-launched ebook outlet isn't all that obvious, but here's why it matters.
Let's use O'Reilly's title "Cooking for Geeks" as an example.
Go to Google.com and type "cooking for geeks" in the search box. You'll get results that look something like this:
The third result features the "Cooking for Geeks" cover. If you click that, you'll go to the Google Products listing for the book. This page focuses on where you can buy the print edition, but there's also a link to "Preview this book on Google Book Search."
If you click the preview link, you reach this page:
On the left side you'll see a big "Google eBook" promo." That's a direct connection to the Google eBookstore.
The connection between SEO, Google's book search engine, and Google's eBookstore is even more direct. Search for a book title, click a result, and you arrive at the Book Search page with the Google eBook promo.
Bottom line: Success in the search world -- be it web search, book search, or any other type -- is all about discovery.