Mobile ad requests across the AdMob network increased by 17 per cent in March to total 7.7 billion globally.

Apple's over-indexing iPhone and iPod Touch held the global handset top spots, accounting for 22.1 per cent of total ad requests.

Interestingly, more than half of Android and iPhone ad requests came from applications, with Android requests increasing by an average of 47 per cent per month between November and March.

By comparison, in the first five months following the launch of the App Store in the US (July-November 2008), requests from the iPhone increased by an average of 88 percent per month.

Other highlights from AdMob's March Mobile Metrics report include:

- The HTC Dream (G1) generated 72 million requests,  giving it 2 a two per cent share of the overall US Market in March. 
- In the US, the HTC Dream (G1) was the number 10 overall device and the number four smartphone, after the iPhone,  BlackBerry Curve, and BlackBerry Pearl. 
- The Android OS now has a six per cent of the US smartphone market and is tied with Palm as the fourth-largest OS. 
- The iPhone generated eight times more US requests than Android in March.
-  iPhone and iPod touch combined generated 23 times more requests than Android globally.