Based on data from a network of 3.9 billion monthly mobile advertising impressions to over 220 million consumers, Inmobi today announced the result of its Mobile Insights Report: Global Edition March 2011. Figures reveal that for the first time ever, Android has surpassed iOS in terms of global ad impression share.

Both mobile operating systems are consistent in gaining global shares, but Android’s growth is apparently more dramatic than that of iOS–a pattern that hasn’t translated to the tablet market, looking at Millennial Media’s own ad network report from this morning. Android smartphones’ success is credited to the varying devices and price points it offers to consumers. It’s widely popular in Asia, Eastern Europe and Africa, up to the point of being an almost complete alternative for PC.

“The global smartphone revolution continues into Q2 2011. The introduction of Android has significantly accelerated smartphone growth, as it brings a wealth of options to consumers. With the increased focus on mobile from global publishers, advertisers and developers the mobile experience has reached the next phase of its evolution,” said James Lamberti, VP Global Research & Marketing at InMobi.

Amazingly, Inmobi network’s escalation of mobile advertising impressions to 21 percent from December 2010 to March 2011 is solely driven by smartphone impressions which surged to 2.8 billion within the timeframe. Global leader Nokia still sits on top of the chain with 40 percent global impression shares but its tight grip is significantly abating. It lost -3.9 share points in 90 days, while competitors Samsung, Apple and HTC are gaining shares at +1.6 percent, +1.9 percent and +2.8 percent respectively. Smartphones account 35 percent of mobile ad impressions ranked in order as Nokia OS, Symbian OS, Android, iPhone OS, RIM OS, and others.

In North America, smartphone impressions grew by 50 percent in just 90 days, accounting for three out of four mobile impressions. Twenty-one percent of advertising growth on the InMobi network is driven by smartphone alone, thus, depleting advanced phone impressions by 19 percent. While iPhone OS raked in +9.7 share points as of March 2011 because of its launch on Verizon Wireless in the US, Android managed to strike it rich with +4.0 share, overcoming OS by 5.2 share points lead. As a result of Android’s intensification, HTC also boosted +6.1 share points and catapulted to North America’s no. 2 spot of smartphone manufacturers next to the iPhone.

“As expected, the introduction of the Apple iPhone on Verizon has given the iOS platform a big boost against the recent Android swell, although it was not enough to retake the top position. With both platforms having strong support, the most interesting story of 2011 will be to watch what happens to Windows Phone 7 and Nokia,” Anne Frisbie, VP Managing Director North America, InMobi.

As a lot of people turn to mobile devices to access the web, and to some people, event to the extent of phasing out web-based PCs, mobile advertising has proven an effective way to reach customers. For instance, automobile company Buick is turning to Millennial Media for direct access to consumers through applications and advertising.