Millennial Media today released a study for advertisers, which says that smartphones generated 45 percent of mobile impressions and feature phones took 34 percent. Connected devices, like the DS, PSP, iPod Touch and iPad account for 21 percent of the U.S. impressions in March 2009.

“We felt that it was now time to spotlight this data for industry watchers who are trying to understand the role of devices and consumer behavior in the overall mobile market,” said Erin McKelvey, senior vice president of marketing at Millennial.

Apple dominated the smartphone sphere, with the iPhone OS generating a 70 percent share of ad impressions, and devices from the company overall generated the largest share of impressions across Millennial’s network at 40 percent.

Source: MediaPost {link no longer active}