A year-long study from Pew Research found that what's said on Twitter isn't always in line with public opinion at large, often differing sharply from a broader slice of the American public. But surprisingly, it doesn't always lean the same way.
The study began in January 2012, cataloging responses to such high-profile events as the race for U.S. president and the State of the Union address.
For some of these topics, such as President Barack Obama's re-election and the ruling on same-sex marriage, the reaction on Twitter tended strongly toward the liberal side of the issue. For Obama's re-election, 77 percent of reactions on Twitter were positive and 23 percent negative, compared with a nearly 50-50 split in traditional polls. And hardly any of the reaction to California's gay marriage ruling was negative on Twitter: Just 8 percent, compared with 44 percent of people polled publicly who gave a negative opinion about the issue.
These particular biases might be expected by some, considering Twitter's demographic skews younger, more urban and more tech-savvy. But on some issues, the social network's bias tended toward the conservative.
The nomination of Sen. John Kerry for Secretary of State in December resulted in just a trickle of positive responses on Twitter — 6 percent, while 32 percent had a negative opinion, and 62 percent were neutral. But public opinion showed a substantially higher 39 percent of respondents being supportive of Kerry's nomination.
Similarly, for the president's second inaugural speech, nearly half of people polled nationwide had a positive opinion, and 22 percent a negative one. Compare that to Twitter, on which a meager 13 percent gave positive expressions — and twice the number of people gave neutral or don't-know responses.
Pew's conclusion: Twitter is simply not representative of the American public, both because it excludes older and less wired folks, while including those under age 18 and people living in other countries.
The rest of the study, with more examples and information on the methodology, can be found at the Pew Research Center's website.
Devin Coldewey is a contributing writer for NBC News Digital. His personal website is coldewey.cc.