• by Mark Walsh  @markfwal, September 13, 2010

There's no question Google's on a roll with Android these days. In the second quarter, sales of Android-based smartphones surpassed those of the iPhone for the first time, and forecasts released by Gartner and IDC last week predict the Google platform will become the second largest operating system worldwide behind Symbian by 2014.

On top of that, a new study on mobile apps from Nielsen today shows that Android users are more likely to click on in-app ads than people using other operating systems, including the iPhone and BlackBerry. The research firm noted that this trend "spells a clear monetization strategy for anyone targeting the fast growing Android user base." If Eric Schmidt is reading the report, he must be thinking, "Take that, iAd!"

But not so fast. For one thing, the percentage of of iPhone users who click on in-app ads -- 29% -- isn't that much lower than Android's 33%. Nielsen also pointed out that Android users are typically younger and less affluent than iPhone users, and less apt to download paid apps. For every two free apps an iPhone user gets, he buys one. That ratio rises to 3.5 free to one paid app for Android customers.

What's more, it's not just how much users click, but who's clicking. An analysis of "heavy clickers" online a few years back by behavioral targeting firm Tacoda showed that a campaign optimized for that population would skew to middle-aged women from the Midwest looking for deals. Of course, that's not necessarily the case with Android clickers. The Nielsen study surveys mobile habits and doesn't try to provide a demographic profile of people who click on in-app ads on Android.

The survey only notes that compared to iPhone users, Android users tend to be younger and not as wealthy. Recent demo data on smartphone users from comScore showed that about 30% of Android users were aged between 13 and 24, compared to 23% for the iPhone. And in terms of income, 35% of Android users made more than $100,000 annually, less than the 47% of iPhone owners who crossed that threshold.

The variance among smartphone users certainly isn't as wide as among Web users, obviously, but marketers may make more subtle distinctions when considering one platform versus another. So a luxury advertiser like Lexus might target older, more affluent iPhone users while a younger-skewing brand like RedBull might opt for Android.

And then there's BlackBerry, where only 15% of users clicked on ads in apps, reflecting its wider struggle to build an app business. Despite BlackBerry overhauling its App World storefront and introducing more consumer-friendly phones like the Torch with an upgraded OS, Nielsen sounded a skeptical note about the turnaround effort. "It remains to be seen whether Research in Motion's new devices and revamped store will persuade BlackBerry owners to embrace mobile apps," the report stated.

To that end, RIM in the last month has acquired enterprise app developer DataViz as well as mobile app storefront creator Cellmania. RIM has also been rumored to have bought mobile ad network Millennial Media to keep pace with Google's purchase of AdMob and Apple's acquisition of Quattro Wireless. But even BlackBerry's 15% proportion of clickers looks large compared to the 1% or so that click once a month on ads on the desktop Web. The only question is how long the novelty of in-app ads will last.