AdMob serves ads for more than 6,000 mobile web sites and 1,000 applications around the world. AdMob stores and analyzes the data from every ad request, impression, and click and uses this to optimize ad matching in the network. This monthly report offers a snapshot of the data to provide insight into trends in the mobile ecosystem.
In February 2009, Apple’s iPhone generated 33% of all smartphone traffic worldwide and 50% in the US.

More in the full AdMob report (pdf) here.
MacDailyNews Take: Bloodbath.