Today in Mobile

A lot of attention is being given to Millennial Media’s announcement today that Android has overtaken Apple’s iOS in ad impressions delivered through Millennial’s network. That’s newsworthy, to be sure, and it adds to the overwhelming evidence that Google’s mobile OS is growing at an unprecedented rate. But Android Market offers far more free apps than other storefronts, and those free apps are far more likely to be ad-supported than premium titles. So Millennial’s data provides an informative view of the in-app advertising market, but don’t take these figures as any gauge of the overall market for mobile operating systems.