• by Mark Walsh  @markfwal, June 29, 2011

Growth in-application advertising helped mobile ad network InMobi increase ad impressions 71% in North America for the three months ending in May. In-app ads accounted for 53% of the rise in impressions and represented more than half (57%) of the total. InMobi has served 13 billion in-app ads to date in 2011 and expects to serve over 50 billion by year-end.

Data released by InMobi Wednesday also showed Android has a growing presence on its network, accounting for 35.5% of impressions in May compared to 30.2% in February. Apple’s iOS enjoyed an even bigger jump, increasing share from 15.5% to 25.4% during the period. Those gains came at the expense of the BlackBerry OS, which fell from 18.1% to 13.8% on the ad network. Get the full report here.