The iPod touch is gaining wider adoption, becoming the No.2 device in the AdMob mobile ad network, with a 4.7 percent share.

This was the key finding in AdMob's December Mobile Metrics Report. According the report, iPod touch requests more than tripled worldwide from November to December, with a particularly large spike in requests the week after Christmas.

"The mobile advertising market is continuing to grow, despite the challenging economy and growth of smartphone share gives advertisers exciting new ways to reach and interact with consumers on their mobile phone," said Nicole Leverich, director of corporate communications for AdMob, San Mateo, CA.

A request refers to when a consumer visits the mobile Web site or iPhone application of a publisher or developer in AdMob's network and sends a request to AdMob for an ad to serve on that page.

While 70 percent of iPod touch requests in December came from the United States, it experienced strong growth across other major markets including Canada, Britain, Mexico, Germany and France.

Combined, the iPhone and iPod touch represent 15.5 percent of all worldwide requests.

"Advertisers have the ability to target their ads to just the iPhone, just the iPod touch or to both and have taken advantage of all three targeting options," Ms. Leverich said.

Other highlights from the December 2008 report:

Smartphone share increased from 22 percent of total requests worldwide in May to 33 percent in December.

Symbian is the No. 1 smartphone operating system worldwide with a 41 percent share.

In Asia and Africa Symbian has more than 90 percent share. However, the iPhone is challenging its dominance in Latin America and Europe.

Google's Android already leads Nokia's Symbian in North America with 2 percent of OS share.

"Overall, Nokia has less of a share of the U.S. market, which directly impacts their ability to take significant share of the smartphone market with their Symbian operating system," Ms. Leverich said.

"It's interesting to see that after only two full months on the market with one device, the Android operating system already has a greater share of requests than Symbian according to our December 2008 Metrics Report," she said.

The iPhone operating system had 32 percent worldwide share in December, up from 6 percent in May. Although it runs the iPhone operating system, the iPod Touch is not included in this number because it is not a smartphone.

Worldwide BlackBerry-maker Research In Motion has 10 percent and Windows Mobile has 9 percent operating system share. Both are strongest in North America and Latin America.

Palm has 4 percent of smartphone OS share worldwide with more than 95 percent of its requests generated in North America.

In the U.S., Palm had 9 percent share in December, declining from 20 percent in July.

"Consumer demographics do vary by both mobile operator and device in the U.S.," Ms. Leverich said. "Generally speaking, Windows Mobile, RIM and Palm devices are more popular with enterprise users and devices like the iPhone are more popular with consumers."

AdMob's full December 2008 Metrics Report and past reports are available at http://www.admob.com/metrics.

AdMob stores and analyzes handset and operator data from every ad request in its network to optimize ad serving.

Each month, the Mobile Metrics Report aggregates this data to provide insights into major trends in the mobile ecosystem.

"Developers that have created an application for the iPhone, such as Urbanspoon or Tapjoy, have run successful mobile ad campaigns targeting the iPhone," Ms. Leverich said. "Smartphones are continuing to increase as a percentage of our network traffic, led by the iPhone.

"Consumers are engaging with mobile data more on these devices and this presents exciting opportunities for mobile advertisers to reach their target audience," she said.