• by Gavin O'Malley , Staff Writer @mp_gavin, August 24, 2011

Who's winning the race to monetize mobile? Well, as of July, Android still dominated mobile ad impressions with a 61% share of the market, according to new numbers from Millennial Media. While Android has led the market for eight consecutive months, Boy Genius Report says the numbers represent a "sizable swing ... for the first time in several months, with Android usage ... increasing from 54% in June to 61%."

Put another way, "Android's growth is something we're already used to, but it's the leaps and bounds that the platform takes that exceeded expectations in July," writes PhoneArena.com.

Meanwhile, Apple's much-maligned iOS came in a distant second with 21% of impressions served during the month. That said, when ad revenue was tracked by platform, Android only bested iOS by 5%, ZDNet notes.

Apple is also the No. 1 mobile manufacturer with 26.45% of the market, closely followed by Samsung with 19.11%.

Poor Windows Phone 7 generated only 2% of ad impressions in July, but achieved a 71% increase month-over-month. "The indicates that more of these phones are in the market each month, and with Mango due to launch soon WP7 could be poised for good growth," ZDNet suggests.

In a different light, Millennial's data reveals that "the mobile network that is benefiting most of all from the smartphone data explosion is not a cellular operator, but the collective power of WiFi," writes paidContent. Indeed, it shows "that a full third of all traffic came from WiFi networks -- which include those from mobile operators but also the many hotspots and networks that are not."

A top mobile ad network, Millennial Media's monthly statistics are recognized by some as a health barometer for the mobile industry.