One of the competitive dynamics of phone books was that businesses were essentially extorted to buy advertising in any phone book whose publisher had the scale

One of the competitive dynamics of phone books was that businesses were essentially extorted to buy advertising in any phone book whose publisher had the scale to give everyone in your town a copy. If you didn't buy advertising in every one of N phone books, you lost roughly 1/N sales for each book you failed to advertise in. More than one empire was built by introducing new phonebook after phonebook to town after town. Despite none of the towns needing another phonebook. So it may be a bittersweet situation that Google's lock on search at least saves businesses from having to advertise in 20 search engines. Although given Google advertising is an auction, maybe there are no savings.