WSJ says that Google’s executives were against using cookies to track people online, but the DoubleClick acquisition changed their perspective.
“For the first time, Google had the ability to deliver ads targeted to individual people’s computers. But just because it had the ability, Google didn’t start using it. There was still too much internal resistance. […] Tensions erupted during a meeting with about a dozen executives at Google’s Mountain View, Calif., headquarters about 18 months ago when Messrs. Page and Brin shouted at each other over how aggressively Google should move into targeting, according to a person who had knowledge of the meeting.[…]Mr. Brin was more reluctant than Mr. Page, this person said. Eventually, he acquiesced and plans for Google to sell ads targeted to people’s interests went ahead.
More Info: Google: Into the Future