While blogs and Twitter are both called social media and have a similar basic function-the sharing of information and opinion-their news agendas differed markedly in 2011 (something we also saw in 2010). The data examined by PEJ reveal that Twitter users were more consumed by new digital technology and products. The blogosphere more closely followed the traditional press focus on current events and issues.

In effect, while similar percentages of adults in the U.S. blog and use Twitter (14% and 13% respectively), they use the two platforms differently. The conversation on Twitter has a distinct and narrower set of news priorities, at least as measured by the top five subjects each week. Bloggers are forging a hybrid news agenda that shares elements with both Twitter and the mainstream media.

To evaluate the most popular topics on Twitter and blogs, PEJ uses a mix of content analysis combined with tracking services that measure the links present in blog posts and tweets. Each weekday, PEJ captures the top five stories on each of four social media tracking sites (Tweetmeme, Technorati, Icerocket and Twitteruly). Our researchers then code each story for its subject matter. On a weekly basis, we tabulate which subjects were present the most often separately for blogs and Twitter. PEJ releases the findings weekly in our New Media Index reports. In August 2011, PEJ made some changes to the methodology that expanded the number of social media tracking sites and expanded the number of sources from which content could originate-thus broadening the sample. 

The 2011 data indicate that, first and foremost, people use Twitter to discuss and disseminate news and reviews about the latest high-tech products. When added together, the three related topics-consumer news, technology and business-made up almost half the stories that made the top five list derived from our multiple tracking services in a given week.

Breaking down that conversation from topic to storyline, in 2011 the four most popular stories on Twitter were, in descending order, news about Facebook, Google, Twitter itself and Apple-all giants of the new information ecosystem. Twitter users displayed an almost insatiable appetite for news and rumors about the latest gadgets and upgrades by the major companies and in many cases, functioned as consumer reporters evaluating these products.

Another category of news more popular on Twitter than blogs was information regarding celebrities, fueled by entertainers who have huge followings on the social media platform. Fully 13% of the top stories in any given week were about celebrity on Twitter. That number was just 4% in blogs. Ubiquitous pop idol Justin Bieber ranked as the fifth most popular story of the year on Twitter; Lady Gaga tied for No. 7.

Considerably less prominent on Twitter were the news events and issues that are fodder for newspaper front pages and cable talk shows. In the year leading up to a presidential election, for instance, the conversation about government and politics was rarely among the top stories on Twitter in any given week. Foreign affairs and diplomacy also represented a small portion of top topics on Twitter, even with such overseas events as the Arab Spring and the Japanese earthquake. Those categories combined accounted for only 9% of the stories that made the top five list in a given week.

Bloggers were also interested in technology and new digital products in 2011, but just not to the extent that Twitter users were. The business, consumer news and technology topics combined to account for about 26% of the top weekly stories, little more than half of what it was on Twitter. Still, Apple, cell phones and Google registered among the top five stories on blogs for the year.

But aside from that, the new priorities in blogs largely diverged from those on Twitter and the blogosphere’s function as a forum to debate public events became more evident.

In blogs, the conversation about government and politics, as well as diplomacy and overseas events, combined to account for almost one-third of the stories in the top five list in a given week. In addition, roughly another third (29%) of the dialogue on blogs was devoted to a series of public policy issues that included the economy, the environment, health care, education and others.

In one indication that bloggers often take their cues from what is happening in the mainstream media, five of the top 10 stories on blogs-the economy, the presidential campaign, health care, the civil war in Libya, and the death of Osama bin Laden-were also among the top 10 stories in traditional news coverage.