Already dominant in the search-engine business, Google is becoming an increasingly important ally to publishers and booksellers--or a threat, depending on your point of view. A growing share of Web users use Google to find what they're searching for online, so Google is a crucial source of new visitors to author and publisher sites.
Meanwhile Google is evolving into an online marketplace connecting book shoppers and publishers, and could become a major competitor to Amazon in book retailing, both with e-books and physical books.