Many newspapers have begun locking their content behind paid firewalls; unless you register and pay, you can’t read their stories. The logic is that they can’t afford to give the news away for free anymore, because their advertising is getting decimated. (Craigslist is utterly destroying the traditional classified-ad market, and classifieds are the most profitable ads in any paper.)

But what happens to a paper’s readership and influence when it puts up the gates in cyberspace? Bloggers don’t link to it, which means it vanishes from Google and spirals into a cycle that eventually erases it from the mindspace of the Internet. The Wall Street Journal has a print circulation of 2,106,774, making it the second-biggest paper in the country, but you’ll almost never find a link to a Journal article in a Google search — because the content is inaccessible and thus never linked to.

In contrast, consider the Christian Science Monitor. Its print circulation is a measly 71,000, ranking it 242nd in size, way behind the Journal. Yet it has 1.7 million unique visitors per month to its web site, because the content is free — and good — and thus bloggers link to it promiscuously. Media pundits often note that more people read the New York Times online than in print, but the Monitor is an even more extreme example of the trend: Its online audience, and thus its online influence, is more than ten times larger than its print one.

Now Berkman fellow Ethan Zuckerman has pioneered a brilliant way to rank papers, based on a super-cool ratio: How many blog-links point to a paper, per thousand copies of print circulation. The short form is “LpkC”; you could also think of it, Zuckerman adds, as a measure of a paper’s “blogginess.” The bigger your LpkC number, the more disproportionately huge is your online influence.

He crunched the numbers on the 20 US papers with the biggest circulation, and added in the 30th, 40th, and 50th, etc., up to the 150th, to get a wide sense of the field. He also threw in the Christian Science Monitor, even though it’s way smaller than the smallest on that list. According to his calculations, here are the top papers, ranked by LpcK number:

Christian Science Monitor - 134.90

New York Times - 63.08

Washington Post - 58.44

San Francisco Chronicle - 38.32

Boston Globe - 29.80

Seattle Post Intelligencer - 18.56

New York Post - 12.48

LA Times - 11.21

Check it out: The tiny Monitor more than doubles the number for the monolithic Times. Interestingly, the mean LpkC for all papers Zuckerman studied was 14.43. When he calculated the papers with the lowest LpcKs, here’s what he got:

Charleston Post and Courier - 0.06

New Hampshire Union Leader and Sunday News - 0.22

Middletown (NY) Times Herald-Record - 0.39

The Wall Street Journal - 0.40

Fort Myers News Press - 0.50

I love it — the Journal’s rating is 337 times smaller than the Monitor’s! Of course, there’s no doubt that the Journal is still a much more influential paper, though given these numbers, I wouldn’t be surprised if its closed-down gamble eventually blows up in its face. If online advertising continues to grow, the Monitor could wind becoming unduly profitable for its size, while the Journal goes in precisely the opposite direction.

The ecology of influence is changing, and fast. Will the ecology of advertising change too?

(Thanks to Techdirt for this one!)