AdMob and comScore just put out results of a study (n=7,300 US mobile users over 13) that contains a lot of interesting demographic and behavioral data about the similarities and differences between iPod Touch and iPhone users. However, by far the most important finding of the study -- consistent with what we've been arguing around here -- is that 40% of those users are going online more often on those mobile devices than through a PC (see graphic below). 

While this is self-reported data, it points toward a near-term future when growing numbers people use their smartphones as primary and their PCs as secondary ways to access the Internet. (See also, here and here for more confirmation of this.) This phenomenon is already true in many developing nations, where mobile phones are outstripping PCs for Internet access -- and where search volumes on mobile devices are approaching or exceeding the PC accordingly.

That single 40% data point alone is the answer to the "why" question of mobile marketing -- not the "4 billion phones vs. 1 billion PCs" statement that one often hears in the first couple slides of a presentation. Another striking finding: "5 in 10 consumers on both iPhone and iPod touch devices use the mobile Web more frequently than they read printed newspapers." Indeed, we just posted "Smartphones are the new print."

Below are slides showing the percentage of iPhone/iPod Touch users who use mobile more than the identified medium:

One could argue that the smartphone is the everything media device: a newspaper, magazine, TV, radio, PC rolled into one. But wait, there's more . . .

And now for the demographic information (verbatim from the release):

• iPhone users are generally older. 69 percent of iPod touch users are between 13-24 years of age, while this same age segment represents just 26 percent of iPhone users. 31 percent of iPhone users are 35-49 years old, while only 12 percent of iPod touch users fall in this age segment.
• In total, 74 percent of iPhone users are over the age of 25, compared to 31 percent of iPod touch users.
• More than 70 percent of users on both the iPhone and iPod touch are male.
• In line with the older demographic composition of iPhone users, they also have higher incomes. 78 percent of iPhone users have an annual household income of at least $25,000, compared to only 66 percent of iPod touch users.
• iPhone users are more likely to have children than iPod touch users, most likely due to the age difference in the two groups. 46 percent of iPhone users have children, compared to only 28 percent of iPod touch users.
• In the next six months, iPhone users plan to purchase clothing (57 percent), entertainment (47 percent), and travel (45 percent), while iPod touch users plan to purchase clothing (61 percent), entertainment (53 percent), and cell phones (36 percent).