Editor's note: Amy Gahran writes about mobile tech for CNN.com. She is a San Francisco Bay Area writer and media consultant whose blog, contentious.com, explores how people communicate in the online age.
(CNN) -- The Nielsen Company gathers lots of useful and interesting statistics about all kinds of media. Recently it compiled statistics from several recent studies into an intriguing visual map of the U.S. media universe as of 2010.
The chart only covers mobile and TV, not radio, newspapers, magazines, books, computer-based web access or other kinds of media that remain popular. Still, it's an interesting glimpse into current American media access and usage trends.
Among the key stats:
• As of May 2010, U.S. mobile users spent more time sending or reading e-mail on their phones than any other internet-enabled mobile activity (comprising 38.5% of mobile internet time spent). Social media was a distant second (10.7%) and reading news/current events was third (7.2%).
• Nielsen reports that 31% of U.S. mobile users have smartphones. This figure echoes similar recent research from Comscore and elsewhere, and is probably pretty solid.
• But Nielsen also found that only 37% of U.S. mobile users access the Web from their phones. This figure sounds oddly low to me.
I recently conducted a survey of 84 mobile users in Oakland, California. I found that two-thirds reported accessing the Web from their phones daily -- plus an additional 14% access the mobile Web on most days.
Now, it could be that Oakland is an unusually mobile-Web-savvy town (even though 70% of our survey respondents rely primarily on simpler, cheaper "feature phones"). However, I suspect that Nielsen's statistic may overlook a large portion of mobile Web users somewhere, perhaps feature phone users, since 37% is awfully close to the smartphone-user market share they cite.
Nielsen's chart does not cite the specific source for that mobile Web usage statistic, so at this point I'd simply say this figure should be used with caution. My own study was small, but it did produce a similar ratio of smartphone-to-feature phone ownership -- and yet an enormously different estimate of mobile Web usage.
Oakland is not like every part of the United States, so I suspect the true national average for mobile Web usage lies somewhere in between.
• Nielsen also listed the top-selling mobile phones, purchased by U.S. consumers between January and September 2010, so it ignores handsets bought before that time that were still in use. (Which is a pretty big part of the mobile market. Users on tighter budgets tend to change phones less often -- and the economy was still pretty tough in 2010 for most Americans.)
The top-selling new handset in the first three quarters of 2010 was the iPhone 3GS. Several retailers began offering this older-model iPhone for $100 or less in 2010, and the iPhone is both pretty easy to use and enjoys huge brand awareness among the general population. But the fact that the 3GS, and not the iPhone 4, was the top seller indicates that cost is still a leading consideration in most consumers' handset choices.
I'd be curious to know what proportion of those iPhone 3GS handsets were being purchased for use with AT&T family plans vs. individual contracts. Adding an iPhone to a family plan tends to be much more affordable than using it on a standard AT&T individual iPhone service plan.
The second best-selling handset in 2010, according to Nielsen, was the Samsung SCH-U450 model (branded as the Samsung "Intensity" or "Doubletake"). This is a mid-range feature phone, typical of the models I often see in use around Oakland. It has a slider Qwerty keyboard, a small screen and a standard numeric keypad. It doesn't run apps, but it does include a Web browser, e-mail and other internet-enabled features.
Next came the Motorola Droid (now an older model, which many retailers are offering at reduced prices) and the RIM Blackberry 8500 series (the "Curve"). Blackberries have consistently been the top-selling smartphone since smartphones began, so it's surprising to see it being outpaced in sales by iPhone, Samsung and Android models.
Nielsen did not report sales totals for each phone model, only how they ranked.
• Finally, Nielsen reports that as of November 2010, the RIM BlackBerry operating system, Apple iOS and Android OS are running nearly neck-and-neck. Apple had a slight lead at 28.6%, but it's unclear whether that figure includes iPad users as well as iPhones.
The opinions expressed in this post are solely those of Amy Gahran.