Who listens to blogging heads?

Daily Kos. Little Green Footballs. Talking Points Memo. Instapundit. Firedoglake. Captain’s Quarters. These are among the thousands of political blogs that are increasingly a factor in U.S. politics. Bloggers and their readers are courted by politicians, as occurred when seven Democratic presidential candidates appeared at the August 2007 convention organized by the readers and posters at Daily Kos, a liberal political blog. Bloggers can also shape the news surrounding election campaigns. It was Huffington Post, a liberal political blog, that first reported Barack Obama’s comment about small-town Americans clinging to “guns and religion.”

Although political blogs have become a familiar presence in politics, we know less about their readers: How many there are, who they are and why they choose their favorite blogs.

In fall 2006, political scientists, including us, representing about 30 universities conducted a survey of 16,000 Americans, the Cooperative Congressional Election Study. The survey asked respondents whether they read blogs and, if so, which ones. We analyzed the answers, and the result is the first detailed portrait of political blog readers.

About 34% of the respondents said they read blogs, but only 14% named at least one blog that focuses on politics. Who are these political blog readers?

Compared with those who don’t read political blogs, they are more likely to have a college degree and, obviously, are more interested in politics. They are more likely to identify themselves as Democrats or Republicans, rather than as independents, and are more likely to call themselves liberals or conservatives rather than moderates. Political blog readers are more likely to vote, give money to candidates or simply talk about politics. They live and breathe politics.

It is their political passion that most distinguishes readers of political blogs. In terms of gender, race, age and income, they are not much different from those who do not read blogs.

Political blog readers tend to read just a few blogs. About 40% of them named only one political blog they regularly visit, and 90% said they read four or fewer blogs.

They also tend to visit blogs that share their viewpoint. Think of such blogs as their red meat. Indeed, 94% read only blogs on one side of the ideological spectrum, with 90% of liberals and 90% of conservatives sticking to like-minded blogs. Self-proclaimed “moderates” don’t blog shop either, with 89% exclusively reading either liberal or conservative blogs.

To determine just how polarized blog readers are, we constructed a measure of political ideology by drawing on blog readers’ attitudes toward stem cell research, abortion, the Iraq war, the minimum wage and capital gains tax cuts. Using this measure, we then arrayed respondents from left to right. Here’s what we found.

Readers of liberal blogs were clustered at the far left, and readers of conservative blogs were bunched at the far right. There was little, if any, overlap between them on these issues. The two sides have less in common politically than, say, liberals who watch PBS and conservatives who watch Fox News.

One caveat, however: We don’t know if blogs polarize their readers, or if highly ideological readers gravitate to blogs that reflect their partisanship.

How might political blogs and their readers affect the presidential campaign?

They will not change many voters’ minds because the vast majority of their readers are already members of the choir and hold strong opinions about politics. Sodon’t expect political blogs to make Democrats vote for John McCain or Republicans embrace Barack Obama. If political blogs change opinions, they will more likely do so indirectly -- by uncovering new information that is then amplified and discussed in media that reach a broader, and less partisan, cross section of the public.

Blogs might affect the presidential campaign in another way: by encouraging their readers to participate in politics.

We don’t mean to vote, because blog readers are already habitual voters and need no extra encouragement from blogs to go to the polls. Instead, blogs may prod their readers to engage in other kinds of political activity, such as giving more to candidates or registering and mobilizing new voters. Because fewer people habitually donate to politicians or mobilize others to vote, blogs have more potential to change these habits. Indeed, some blogs put mobilization over persuasion.

As one contributor to Daily Kos put it, “This is not a site for conservatives and progressives to meet and discuss their differences ... the efforts here are to define and build a progressive infrastructure.”

It may take a long time to build this kind of infrastructure. But in the short term, political blogs can still motivate enough “netroots” activists to attract the attention of candidates. The 2008 election may tell us just how much blogs helped in electing the winning candidate.

John Sides and Eric Lawrence are assistant professors in the department of political science at George Washington University. Sides blogs at themonkeycage.org.