The latest figures from AdMob suggest that over 50% of O2 UK customers and almost 5% of Vodafone UK customers are using an Apple iPhone. AdMob delivers advertising to the mobile web, which means it’s able to track the devices its ads appear on. In May 2009 the company handled over 282 million ad requests for UK customers, with the bulk of its requests – 48.7% of all ads – delivered to Apple devices.