Twitters users differ on how frequently they check the service to monitor material from their networks. A little more than a third check daily while a comparable number say they rarely check the site.

Most users post a mix of personal and work-related information. A majority say that they post “humorous or philosophical observations.” And if your business is interested in tracking down these users to serve them messages and ads, the study reveals that 24% of respondents use the service to tweet their location, with 7% of them doing so on a daily basis.

A pair of surveys from the Pew Research Center’s Internet & American Life Project shows a rapid decline in blogging among teens and young adults and a modest rise among people 30 and older. To quote the study: “In 2006, 28% of teens ages 12-17 and young adults ages 18-29 were bloggers, but by 2009 the numbers had dropped to 14% of teens and 15% of young adults. During the same period, the percentage of online adults over 30 who were bloggers rose from 7% in 2006 to 11% in 2009.”

Overall, blogging has leveled off among adults over the past few years, hovering around 10-12% of Internet users.

Amanda Lenhart, lead author for the studies, told me that among those under 30, the shift away from blogging follows their migration to newer social networks and technologies such as mobile devices. “We attribute some of the decline among young adults to the move away from MySpace, which made blogging a prominent feature of a profile, to Facebook, which does not offer the same opportunities to engage in an activity that the site terms blogging.”

Researchers elsewhere have measured the same declining interest in blogs, but for other reasons:

• A year ago Adweek reported that Internet use had reached a plateau and the growth of blogs had flattened. According to Forrester Research, the number of households with Internet access grew 3 percent from 2008 to 2009. Slightly less than 20 percent of respondents reported reading blogs, the same figure as 2008.
• That week ReadWriteWeb reported research from Universal McCann that showed blogging has reached a saturation point. “UM notes that 71% of users report reading blogs—an increase of only 1% since [2008].”
• In February 2010 HubPages’ Larry Freeman wrote that growth in U.S. traffic at major blogging sites WordPress and TypePad has flattened. The one contradictory statistic: U.S. traffic at Blogspot has grown by about 40%.
• In June The Economist reported that traffic at two of the most popular blog-hosting sites, Blogger and WordPress, is stagnating, according to media research firm Nielsen. “By contrast, Facebook’s traffic grew by 66% last year and Twitter’s by 47%.”

Anecdotal evidence from the B2B world supports the studies. In a post, Matthew Ingram says he knows of several entrepreneurs who have replaced their free blogs in favor of subscription-only email newsletters. And Michael Hickins reports on BNET that while the number of active communities at network storage company EMC has increased by nearly 30% over two quarters, the number of blogs has dropped by 70%.

What could lead to such a leveling of blog activity? Lack of time and attention to start. And the perception that the activity isn’t valued by others and doesn’t contribute to the writer’s income or ego. Maybe there’s a growing realization that, while anyone can become a publisher, not everyone wants to read our thoughts.

Citizen journalists are discovering what mainstream media have known for centuries: people’s attention is just as valuable and elusive as their time. Engaging it requires a lot more than a forum.