Apple aquired mobile advertising network Quattro Wireless for US$275 million in January this year. The move put Apple in direct competition with Google following the search giant's purchase of AdMob for US$750 million in November last year.
Announced in April, iAd was developed exclusively for Apple iPhone, iPad and iPod Touch, giving third parties access to the audience behind the range of mobile devices through interactive rich-media ads inside apps.
Former Quattro CEO and Apple iAd vice-president Andy Miller said in a memo to Quattro participants, "We believe iAd is the best mobile ad network in the world, and starting next month we're going to focus all of our resources on the iAd advertising platform."
The company is no longer accepting campaings for the Quattro network and will cease running campaigns at the end of September.
The Wall Street Journal reports that iAd has been slow to take off, some blaming Apple's tight control over the ad making process for the delays.