The Online Publishers Association has released "A Portrait of Today's Smartphone User."
Here's an excerpt from the press release:
The OPA collaborated with Frank N. Magid Associates, Inc. to conduct the study, which found that the population of smartphone users is growing rapidly. An estimated 44% of the U.S. internet population, ages 8-64, owns a smartphone (107 million consumers*), up from 31% in 2011 (73 million consumers*) and expected to reach 57% by Q2 2013 (142 million consumers*). Aside from making phone calls, 93% of smartphone users regularly access content and information above any other activity, followed by accessing the internet (59%) and checking email (58%). The primary types of content smartphone consumers access are weather information (47%), video (31%), local news (29%) and national news (24%).