Mobile ad serving network AdMob receives 2 billion ad requests per day

"Google’s mobile ad network AdMob is releasing a number of staggering statistics today as the network begins its first full year under the Google umbrella. Google says that AdMob is receiving 2 billion ad requests per day, a data point which has quadrupled over the past year. To put that in perspective, as of May of 2010, AdMob was receiving nearly 1 billion ad requests per month."
Source:  Techcrunch, 6th January 2011