Mobile advertiser Mobclix put together this infographic supposedly showing the "monthly value of an app user." It's the monthly advertising revenue for each app category listed, divided by the average number of users in a given month. As you can see above, iPhone apps are clearly generating more revenue per user than Android apps across the board, and Utilities apps top the list in terms of monthly value per user, as compared to Entertainment and Games apps.
Before you start building an ad-driven Utility app for iPhone, though, don't forget that this chart basically sidelines the population stat. While the "value per user" on Games apps seems low, that's only because there are so many more users in that category. Lots more people, believe it or not, use their smartphones to play games than do actual work. Likewise for the Android listings; we already know that Android mobile app sales aren't quite as high as iPhone app sales, though there are more Android handsets out there than iPhones already.
This is more of an interesting look at the people who use the apps. Utilities users on the iPhone tend to be a little more valuable as app users, while Games users are relatively cheap and plentiful. That's a pattern we've seen on platforms before, and things will likely stay that way even as the market for mobile advertising gets even bigger.