New data from M:Metrics for the month of January confirms that folks who own an iPhone tend to do more entertaining things on their devices — such as watch video and visit social networks — than those who own smartphones. However AdMob points out that iPhone users are still a relatively small part of the overall mobile phone market in the U.S.
http://gigaom.com/2008/03/18/iphone-users-are-having-more-fun/