It's always important to point out that AdMob's data come from its network, which is not the same thing as the mobile Internet as a whole. Certain trends may be exaggerated or underrepresented accordingly. But I believe that directionally the data capture what's going on in the broader market. With that caveat, AdMob has released its December, 2009 metrics report. 

This report captures handset and smartphone operating system share around the world. Here are some of the regional bullets the company has released:

• Asia: Nokia continues to be the leading manufacturer in Asia by a wide margin with 53% of requests in Q4 2009.  After launching in several countries in Asia in 2009, the iPhone had a strong Q4 and doubled its share of smartphone requests to 27%.
• Eastern Europe: Nokia’s share decreased slightly throughout the year to 35% in Q4 2009.  Apple, Sony Ericsson, and Samsung devices generated 23%, 12% and 9% of requests, respectively.  Eight of the top 10 smartphones in the region were Nokia devices, including the 6300, N70, and N95.
• North America: In Q4 2009, Apple lead with 40% followed by Samsung with 17% and Motorola with 11%.  The iPhone generated 54% of smartphone requests in Q4 2009. Android share grew throughout the year reaching 27% in Q4 2009, by far its highest penetration in any region.
• Western Europe: Apple made strong gains in manufacturer share in 2009. In Q4 2009 the Apple iPhone and iPod touch generated more than half of total requests from the region at the expense of Nokia, Samsung, and Sony Ericsson.  Android had a strong Q4 2009 and generated 8% share of smartphone requests, second only to North America in penetration.

 Here are the market share graphics . . . 

Global manufacturer and smartphone operating system share: 

 Devices Western Europe:

 Devices North America:

North America shows strong Android growth above (though it's off in Europe), while Palm is fading. In particular Droid showed significant growth vs. the previous quarter. In AdMob's data BlackBerry is flat or off (BlackBerry had huge international sales last year, which should show up at some point in AdMob's data). Finally Windows Mobile is MIA in these data. 

Nokia should see these data (as well as others in the market) as alarming. Symbian will get an update and new UI upgrades this year but it may not be enough in the face of iPhone, RIM and Anroid competition. Nokia has a very strong position in Asia, Africa and Eastern Europe but it's losing momentum everywhere else according to AdMob.