• by Mark Walsh  @markfwal, April 14, 2011

Android may have surged ahead of iOS in market share among smartphone platforms, but it still rules when it comes to mobile applications. The latest monthly metrics from Millennial Media show that in March Android maintained its dominant presence on the mobile ad network, accounting for 48% of impressions. Apple's iOS had 31% and Research in Motion's BlackBerry OS had 18%.

But when it comes to generating ad revenue from applications in the Millennial network, the share is almost the reverse, with iOS accounting for 47% of in-app ad dollars, and Android, 36%. BlackBerry devices drove 7% of app ad revenue, and all other platforms including Windows Phone 7, Symbian and webOS, 10%.

A study by mobile ad exchange Mobclix in January found that advertising on iOS was significantly more effective than Android in yielding revenue from in-app ads, making Apple device users more "valuable" to developers and advertisers.

Helping to drive Apple's commanding share in apps was a month-over-month doubling of app revenue on the iPad. Growing sales of the Apple tablet also helped to expand the connected devices segment on Millennial's network, accounting for 17% of impressions in March compared to 14% the prior month. The connected device share is now approaching that of feature phones -- 19% -- while smartphones are responsible for the vast majority (64%) of impressions.

Apple was the top device maker overall on the Millennial network, with a 32% share of impressions. Samsung was a distant second with 15%, followed by HTC and Research in Motion (tied with 10.6%), and Motorola at 9.6%.

The iPhone was again the top handset with a 19.4% share, while the BlackBerry Curve reclaimed the No. 2 spot with a 5% share. The HTC Bro, Samsung Epic and BlackBerry Bold 2 rounded out the top five devices. All Android devices combined represented 22% of impressions among the top 20 smartphones tracked by Millennial.