Millennial Media

Android scooped up more than half of all ad impressions seen by Millennial Media last quarter, according to the ad network's new MobileMix report.

For the first quarter, Android won 52 percent of all impressions (the number of times a mobile ad is displayed), up from 49 percent in the year-ago quarter.

In second place, iOS accounted for 39 percent of all impressions, up from 33 percent. That left the third spot to the BlackBerry OS, which saw its slice of ad impressions cut in half to 7 percent from 14 percent. Microsoft's Windows Phone also witnessed a drop to 1 percent from 3 percent in the prior year's first quarter, while Nokia's Symbian remained flat at 1 percent.

Apple remained the dominant device maker by capturing 36.8 percent of all impressions, followed by Samsung with 27 percent.

Android tablets accounted for 45 percent of all ad impressions among tablets, a gain of 96 percent from the year-ago quarter. Samsung's Galaxy Tab was the top Android tablet, followed by Amazon's Kindle Fire. Amazon reached seventh place among the top ten device makers thanks to sharp growth in its Kindle tablets and e-readers.

However, Apple was still tops in the tablet world, with the traditional iPad and the iPad Mini grabbing 54 percent of all impressions among tablets.

Millennial Media generated the report based on its mobile advertising platform, which collects data from "tens of billions of monthly ad requests," according to the company.