Nielsen (NLSN), which is fighting hard to be for mobile media what it was for television, pulled out all the stops in its State of the Media report for the third quarter of 2011.

Drawing on monthly surveys of 25,000 Americans (300,000 per year), it found, among other things:

• 44% now carry smartphones. Ownership is highest among 25-34 year olds (64%) and  18-24 year olds (53%).
• Google and Apple are both No. 1. Apple (AAPL) is the top smartphone manufacturer (28.6 market share, up from 27% in a Jan. survey) and Google’s (GOOG) Android is most favored operating system (44.2%, up from 29%).
• Their share of the app market is even higher. The iPhone and Android phones account for 83% of U.S. smartphone app downloads.
• Different apps for different age groups. Older folks like games, such as Angry Birds, and rely on their mobile devices for productivity. Younger Americans are more likely to use entertainment apps with social dimensions (e.g. Pandora, YouTube, Words with Friends).
• There’s an awful lot of texting going on. In Q3 2011, American teenagers 13-17 sent and received an average of 3,417 messages each month. Now their parents are texting too. The number of messages sent by users 55 and older has more than doubled from 2009.
• Memo to marketers. 49% percent of mobile consumers say they often use their smartphones while shopping.
• Facebook is hot hot hot. Android and iPhone users say they spend more time on their mobile Facebook than any other.

You can see the full report here.

Below: A year’s worth of Nielsen market-share snapshots.