[youtube http://www.youtube.com/watch?v=Aqn9ILQpqEo&w=560&h=349]

iPhone may be the most popular smartphone. Android devices are growing in popularity. But if you're an advertiser looking to get the biggest bang for your mobile advertising buck, you should be looking at Windows Mobile phones. According to a study by Smaato, an optimizer for mobile ad networks, the platform with the highest click-through rates is Windows Phone. Coming in second was the Symbian OS, and trailing behind were Android and iPhone. Smaato's CEO, Harald Neidhardt, says one reason for Windows Mobile's success may have to do with a combination of its newness and less advertising overall, meaning the few ads there are stand out and are more effective. He suggests that if you don't have a Windows Mobile phone app now, it might be worth it create one because of the potentially higher monetization opportunities. Few Ad Requests Being Filled The other surprising statistic from Smaato's was the 18 percent fill rate for ad requests. That means one in five requests from a single ad network to place an ad in a mobile app are filled. Individual developers looking for more ads in their apps, should make more requests to multiple ad networks and/or look to ad network consolidators such as Smaato, Neidhardt advises.