To the purist, few things are smellier than advertising, and once you step in it, there is no easy way to fully wipe it off. Yet the time had come when Google had to show it could make money somehow. As pure as they were, Page and Brin also admired efficacy. Neither much respected idealists who never got anything done, the high-minded academics and programmers whose eyes and ideas never saw daylight. Google had come too far to founder on its own ideals.

Tim Wu, The Attention Merchants, loc. 884