AdMob highlighted widespread mobile Internet usage on WiFi in the United States and strong growth in Western Europe in its January 2009 Mobile Metrics Report.

Consumer usage of WiFi to access the mobile Internet is widespread across the U.S. and the West and Northeast experienced heavier WiFi usage by population than the South and Midwest in January. The states that generated the most WiFi traffic are California with 18 percent, New York with 14 percent and Texas with eight percent.

"What we did is look at mobile Web usage on WiFi across the U.S.," said Nicole Leverich, director of corporate communications for AdMob, San Mateo, CA. "WiFi usage is widespread and the West and Northeast had more usage than the East and the Southwest.

"I think it's significant for mobile marketers because this means that consumers access the mobile Web through their carriers," she said. "It is also important to note that a lot of people are accessing the Web on mobile Internet devices and not just on mobile phones."

AdMob claims to serve ads for more than 6,000 mobile Web sites and 400 applications around the world. AdMob stores and analyzes the data from every ad request, impression, and click and uses this to optimize ad matching in the network.

The company's monthly report offers a snapshot of the data to provide insight into trends in the mobile ecosystem.

AdMob found that worldwide requests increased 8 percent month over month to 6.8 billion, led by double digit growth in Western Europe and Asia.

Traffic from Western Europe increased 132 percent in the last year to total 550 million requests in January, with Spain and Italy growing the fastest.

The iPhone is now the number one device by usage in Western Europe with 31 percent share of total requests. This strong share reflects dramatically higher mobile Web and application usage by consumers on this device.

Nokia and Sony Ericsson are the No. 2 and 3 manufacturers in Western Europe, with 22 percent and 17 percent share, respectively.

Nokia continues to dominate the smartphone category with 11 of the top 15 devices.

Windows Mobile has 5 percent share of market in Western Europe with only one device, the Samsung i900, in the top 15. Worldwide the Windows Mobile OS has 8 percent share of smartphone requests.

AdMob claims it is the world's largest and highest quality mobile advertising marketplace, serving more than 4.5 billion mobile banner and text ads per month.

"Mobile marketers should be aware that there is this new range of devices out there from which consumers are accessing the mobile Web," Ms. Leverich said. "Marketers can extend their reach by finding new opportunities and new ways to engage these Web users."