Here are some highlights from the most recent AdMob metrics report, released a couple of weeks ago:

• This month's summary is short and sweet: the iPhone OS (includes iPod Touch) continues to dominate the AdMob network as far as market share goes. It accounts for 65% of all HTML site requests, and 43% of mobile website requests. Android is creeping in at 9% (HTML) and 3% (mobile) respectively, and Symbian represents 7% (HTML) and 36% (mobile). Optimize for these devices first, and you are likely covering the majority.
• RIM's market share continues to decline each month. The manufacturer now only has a 3% worldwide market share, 5.6% in the US and only has 2 phones in the top 20.

The following stats are based on 7,535,272,901 requests:

Top 5 Countries

1. United States (47%, -0.5%)
2. Indonesia (10.8%, +1.6%)
3. India (5.9%, -1.7%)
4. Philippines (4.0%, +0.1%)
5. United Kingdom (3.4%, +0.5%)

Top 5 Worldwide Handsets

1. Apple iPhone (15.1%, +1.9%)
2. Apple iPod Touch (11%, +2.2%)
3. Samsung R450 (2.4%, +0.5%)
4. Motorola RAZR V3 (2.3%, -0.4%)
5. Nokia N70 (2.0%, -0.1%)

Top 5 US Handsets

1. Apple iPhone (20.0%, +3.0%)
2. Apple iPod Touch (14.8%, +2.6%)
3. Samsung R450 (5.2%, +1%)
4. Motorola RAZR V3 (4.4%, -0.7%)
5. Motorola Z6M (2.7%, -0.3)

Download the full report here: http://www.admob.com/s/solutions/metrics