It has emerged that US watchdog the Federal Trade Commission (FTC) is launching an official probe into Apple’s practices regarding mobile advertising on the iPhone, to establish whether the Californian firm is unfairly exploiting its power.

Although the share of feature phone traffic in AdMob’s network declined from 58 percent to 35 percent year-over-year, absolute traffic from feature phones still grew 31 percent. Mobile Internet devices experienced the strongest growth of the three categories, increasing to account for 17 percent of traffic in AdMob’s network in February 2010.

US companies Apple and Google have edged closer toward a head-to-head clash in the mobile industry with their respective announcements of mobile-ad-network purchases and Google’s handset launch this week. Mobile advertising has been put firmly back on the agenda, and the stage has been set for a fierce battle between the two California-based giants for dominance in the smartphone and mobile Web markets.

The mobile industry is buzzing about Internet giant Google’s proposed $750m, all-stock acquisition of mobile advertising network AdMob, which was announced November 9. It is a huge deal, and seemingly an acknowledgement by Google that it has not been able to sufficiently develop its own mobile advertising capabilities internally, even though it has been offering mobile display search advertisements for some time.