AdMob has released its monthly Mobile Metrics Report for March, and to no one's surprise, the iPhone and iPod touch are still hot devices for surfing the web on the go. Both are also hot devices for using mobile apps, too, as AdMob says that over half of the requests for ads from iPhones now come from third-party apps.
Worldwide, the iPhone continues to gain a significant share of mobile requests on AdMob's network. While Symbian-based devices, mostly from Nokia, continue to lead, the iPhone is catching up, mostly to Symbian's detriment. In the US, the iPhone still holds half of all requests for mobile ads compared to devices based on other OSes.

As far as the competition is concerned, Symbian is dropping significantly worldwide, and it is still barely a blip in the US smartphone market. RIM continues to mostly hold steady both worldwide and in US while Windows Mobile continues to decline. Palm continues its downward

slide, while Android catches up to it, both tying worldwide at three percent and in the US at percent percent of mobile ad requests. Competition between the two should heat up when the Pre is released, but with new models expected from Apple and more devices starting to use Android this year, momentum could keep Palm from making significant strides.
AdMob compared growth in ad requests between Android and iPhone for the first five months since the launch of the respective platforms' app stores. Android managed to grow and average of about 47 percent since November 2008. The iPhone grew an average of 88 percent for the first five months its app store was open. AdMob noted that traffic on both platforms is split about evenly between apps and mobile web requests, suggesting that apps are driving mobile traffic as much as full-fledged browsers.
The iPhone and iPod touch continue to rank one and two as the top handsets worldwide and in the US for mobile traffic. Motorola's RAZR still holds the number three spot in both rankings, but continues to slip in share. Apple is the top handset manufacturer in the US by a large margin; while it still ranks number two to Nokia worldwide, it is closing in on Nokia as it cedes some share to Apple.
As usual, AdMob's data comes with the usual caveat that it doesn't measure market share as a percent of unit sales. Instead, it measures the percentage of requests for mobile ads from its network of 6,000 websites and 1,000 applications. Still, the trends it shows in how different devices are being used online is clear. iPhone OS and Android-based phones are moving up, up, up, while Symbian, Windows Mobile, and Palm are going down, down, down. RIM's devices, for the most part, are holding their own.