The iPhone has already become one of the most widely-used mobile devices for exploring the web on a global basis - even though it’s only available in four countries.

The latest AdMob research confirms the trend toward iPhone unlocking for use of the device in countries outside those it’s officially offered in. Cult of Mac recently ran an image of Ukranian president, Viktor Yushenko, talking on his iPhone in a report describing the buoyant trade in those devices in the country.

AdMob stores and analyses data from every ad request, impression, and click and use this to optimise ad matching. “Every day, we see ad requests from more than 160 countries. Each month, we analyse this data to produce our AdMob Mobile Metrics Report covering manufacturer, device and country-specific data on AdMob’s top four markets by impressions served: US, UK, India and South Africa.”

The latest report reveals that 25 per cent of ad requests in the AdMob network worldwide were form Smartphones, while the iPhone moved into AdMob’ top 20 devices on a worldwide basis. While the majority of iPhone clients came from the US and Germany, iPhones also made a significant statistical dent from Canada, Mexico, Hong Kong, Brazil and the Netherlands, none of which officially have iPhone’s on sale yet.