http://www.nytimes.com/2008/06/02/technology/02google.html?ref=media

<<Mr. Fox is among a small group of Google employees who keep a watchful eye on the vital signs of one of the most successful and profitable businesses on the Internet. The number of searches and clicks, the rate at which users click on ads, the revenue this generates — everything is tracked hour by hour, compared with the data from a week earlier and charted.>>

Google several times now allowed the New York Times to report on some internal processes, see also:
http://www.nytimes.com/2007/06/03/business/yourmoney/03google.html?pagewanted=all