Mobile ad network AdMob has moved aggressively into the iPhone ad market, and it's paying off.
Last month, the company served up 1.2 billion ads worldwide to Apple (AAPL) iPhone and iPod touch devices, In Feb. 2008, it served up about 33 million ads to iPhones, or about 1.3% of its 2.56 billion total ad requests. So while AdMob's overall business has more than doubled year-over-year, its iPhone business has grown much, much faster.
Much of the credit goes to Apple: It's sold more than 30 million iPhones and iPod touches, most during 2008. But give AdMob credit, too: It's been a leader signing up iPhone publishers to its ad network, including iPhone-specific ad units for apps sold through Apple's iTunes App Store and delivered on the mobile Web.
TechCrunch got this line directly from AdMob's report -- but that's the problem. While the iPhone may represent 50% of smartphone traffic on AdMob's network, that is not necessarily an accurate depiction of the broader mobile Web. Why not? AdMob's stats significantly favor the iPhone because of its vast ad inventory in iPhone apps -- ads that are not available on other phones -- and on iPhone-tailored Web sites, which won't work on some phones.
So while AdMob's stats offer a nice look inside their mobile ad business and could be directionally correct in a broader context, they are not an accurate, normalized gauge of overall mobile Web traffic.