Mobile ad optimization and advertising agency Smaato has released its latest global mobile advertising metrics. Smaato's Worldwide Index, which analyzes ad network fill rates and sheds light on clickthrough rates (CTR) segmented by handset operating system, geography and response times, is based on data collected from 35 mobile ad networks and over 4 billion ad requests served in the Smaato network of more than 3,000 registered mobile publishers in February 2010.
Overall, Smaato's metrics show that the average worldwide ad network fill rates remain constant at 29% in February 2010. The fill rate is measured as the percentage of ads delivered per ad request, and varies by different factors such as country, device and content type.
Smaato's Index also provides a breakdown of CTR data, segmented according to operating system, showing that Symbian continues to lead the pack, with Android a distant second. However, there are some significant shifts that indicate the gap between operating system CTRs could be closing fast. For example, BlackBerry comes in at 51, up from 30 in December 2009, while Symbian still the dominant operating system has dropped slightly. It comes in at 147, compared with 173 in December 2009.
The biggest surprise, however, is the lead that Windows Mobile has over Apple. Specifically, the iPhone and iPod touch show a declining CTR, coming in with a rate of 89. This is the first time Apple devices have dipped below the average Index of 100, and the first time that Windows Mobile has edged ahead of its rival. In December 2009, the iPhone posted a CTR Index of 119, sliding to 104 in January 2010.
A more detailed analysis of the Smaato Worldwide Index, which covers the ad fill rates of the global top 10 ad networks and a special focus on the fill rates of mobile ad networks in the US and Southeast Asia, is available on MSearchGroove.  
Overall, the best performing mobile ad network in the Smaato Worldwide Index had a fill rate of 72% in February 2010, down 17 from January. Despite this decrease, the average for worldwide ad network fill rate performance remained steady at 29%. What's more, Smaato found that six of the top 10 ad networks performed above this average. This re-enforces the pivotal importance and advantages of the network aggregation business model, says Smaato, which aggregates 35 ad networks across the globe to ensure partners get the highest possible fill rate.
Publishers struggle to identify, in real-time, the right ad network to deliver the right results,” notes Peggy Anne Salz, Chief Analyst at MSearchGroove. “Smaato's aggregation model, which has gained traction globally through its ability to dynamically identify the ad networks that monetize publishers' inventory best, is core to Smaato's competitive advantage.”