50 Million Americans visited 400 blog domains in the first quarter of 2005 – In a report that is sure to get noticed by media execs, national advertisers, and blog entrepreneurs, comScore Networks released a study of blog visitors and their behavior:

comScore Networks today released a report detailing the scale, composition and activities of audiences of Weblogs, commonly known as “blogs.” The report, which was sponsored in part by Six Apart and Gawker Media, found that nearly 50 million Americans, or about 30 percent of the total U.S. Internet population, visited blogs in Q1 2005. This represents an increase of 45 percent compared to Q1 2004.

Other key findings of the Behaviors of the Blogosphere report include:

• Five hosting services for blogs each had more than 5 million unique visitors in Q1 2005, and four individual blogs had more than 1 million visitors each
• Of 400 of the largest blogs observed, segmented by eight (non-exclusive) categories, political blogs were the most popular, followed by “hipster” lifestyle blogs, tech blogs and blogs authored by women
• Compared to the average Internet user, blog readers are significantly more likely to live in wealthier households, be younger and connect to the Web on high-speed connections
• Blog readers also visit nearly twice as many web pages as the Internet average, and they are much more likely to shop online

“The fact that we found 30 percent of the online population to have visited blogs clearly underscores the commercial importance of consumer generated and driven media,” said Dan Hess, senior vice president of comScore Networks. “It’s noteworthy that while the blog audience is already quite large and growing, its demographic composition relative to the total population will appeal to many marketers.”

Here is a link to the report.

Reactions and commentary:
* Fred Wilson: even more interesting is the difference in the way the “youth” blogging platforms like Xanga and Live Journal and the “mature” blogging platforms like Blogspot and typepad are used…Clearly the “youth” blogging platforms are “stickier”.

* John Battelle: As someone who is starting a business in the blog space, I’m pleased. But I hope we remember as we generalize about “the blogging audience” that at the end of the day, it’s not about generalizing, it’s about endemic, passionate communities

* Nick Denton: There’s only one measurement that matters, however, to media buyers at the ad agencies. comScore found that, while 37% of internet users had annual household income in excess of $75,000, 41% of blog readers were in that top band.

* Jeff Jarvis: comScore says that blogs are now big media.

A shocker for many is just how different the top 25 blogs are – as ranked by visitors – as compared to the links analysis that traditional blog related tools provide. In fact – this list will freak some out entirely.

Another shocker will probably be the domination of visitors coming to blogs for for politics and news. 43 percent of all visitors. This should raise the eyebrows of many who look down on blog driven sites for sources of them.

A major problem with this report – as a way to judge the ‘top 25 blogs’ – is that is that blogs that are hosted on by blogging services are entirely lost in the data since this report sums entire hosting domains – that is if I understand it correctly. So no ranking for Atrios for example. Which is flawed to say the very, very least. Possibly they will release this data so that folks can drill down. I hope SixApart will convince them to do so if they don’t plan to. Otherwise – well this is just one more reason for folks to not use these hosted services and to get their own domains.

One unfounded conclusion, however, could be that folks on average – reading and visiting blogs – DO NOT SHARE the linking behavior that many have come to expect, and rely on, as a way to judge the size, growth, and influence bloggers and blogging.