We already know that the iPhone is used more than any other mobile devices to surf the Internet wirelessly. But according to mobile metrics research form M:Metrics, that's not the end of it.

M:Metrics has released data that shows iPhone users also listen to music, access social networking sites, watch on-demand video and mobile TV, and access news and other information far more than both other mobile phone owners, including other smartphone users.

For instance, 74.1% of all iPhone users report listening to music on their phone, compared to 27.9% of smartphone users and 6.7% of overall mobile users. And 84% of iPhone owners who also own an MP3 player say the iPod is their device of preference, suggesting a properly designed musicphone can take the place of a stand-alone music player.

Individual applications also see high usage spikes on the iPhone, which is why so many developers want to write for the newly released iPhone software development kit. More than 30% of iPhone users have accessed YouTube via the device, compared to 1% of other mobile subscribers, and 36% accessed Google Maps, compared to 2.6% of all mobile subscribers. Both applications are installed on the iPhone at sale, and have dedicated icons on the main menu.

"Beyond a doubt, this device is compelling consumers to interact with the mobile Web, delivering off-the-charts usage from everything to text messaging to mobile video," said M:Metrics senior analyst Mark Donovan in a statement. "While the demographics of iPhone users are very similar to all smartphone owners, the iPhone is outpacing other smartphones in driving mobile content consumption by a significant margin."

Along with the iPhone's design and interface characteristics, Donovan also credits the unlimited data plan with AT&T Mobility that iPhone buyers get when activating their device as a significant factor. Most mobile operators don't charge flat rates for the data usage on their networks, which sometime leads to surprisingly expensive monthly bills. AT&T's unlimited data plan eliminates this "bill-shock," except when roaming outside of the AT&T network.

"Our data shows that once the fear of surprise data charges is eliminated, mobile content consumption increased dramatically, regardless of device," Donovan said.