When outside.in released its list of the Ten Bloggiest Neighborhoods in April, the USA Today got interested in the story, but instead of neighborhoods, they wanted to know what the bloggiest cities in the U.S. were. Phillip Lamplugh and Hillary Byrum, our resident Blogiology Experts, ran the numbers on the sixty cities we’ve been tracking and came up with a list, which USA Today then turned it into one of their most excellent graphical snapshots:

And there you have it – Boston is now officially the ‘bloggiest’ city in the U.S., with Philadelphia, Pittsburgh, Washington and Portland coming in on its heels.

Immediately the press wanted to know: why Boston? What makes it so bloggy? Why isn’t San Francisco on this list? And what about New York City?

Well, the figures represent the total number of place-based blog posts in March and April per 100,000 residents in the cities’ metro areas. So to arrive at this list we just took the total number of place-based blog posts in a city’s metro area, and divided by the number of people living in that area.

As far as why Boston and not NYC or SF, we see two possible factors influencing the list:

1. The demographics of a city’s metro area strongly shape its blogginess quotient. Cities like New York may have areas, like Brooklyn, that are very blog-dense, but if they also have big areas where blogs are sparse (like the Bronx), that will lower their overall post-to-resident ratio, making them less-bloggy cities. Chicago, Los Angeles and New York all scored lower on the list for this reason – they had lots and lots of local blog posts, but the sheer number of people living in those areas blew that number away. If your metro area has 19 million people in it, you’ve got to do a lot of blogging to get on the bloggiest cities list.

2. Blogginess in a city is reflective of growth, civic activism, and a writerly population. Boston, as the bloggiest city, has a hot economy, is notorious for local political activism, and has a university every other block, which all combine to push it’s post-to-resident ratio up-up-up.

When you factor these two things together, you get a list of mid-to-large-sized cities with neighborhoods in flux, active local political scenes, and residents with the inclination to write about these things. The result is the bloggiest cities in America list. Here’s the full top ten:

1. Boston
2. Philadelphia
3. Pittsburgh
4. Washington, D.C.
5. Portland, OR
6. New York
7. San Francisco
8. Seattle
9. Chicago
10. Los Angeles

It’s also important to note that this is all in fun, and while it does represent an honest effort to answer questions about blogging around the nation, it doesn’t approach anything on the level of scientific inquiry. That’s for 2008.