ESPN’s Bill Simmons is the most popular sportswriter in America. He’s arguably the only one that really matters anymore. He’s enough of a common denominator that if you end up in a semi-decent conversation about sports with a stranger under 45, that both of you read his column is a very safe assumption.

His popularity is such that his 700 page book about basketball went to number 1 on the New York Times Bestseller List in its first week. His book signings have attracted fans in the high hundreds. His columns’ page views are measured in millions. He’s unquestionably a star.

And his ascension represents ESPN’s biggest new media failure.

Simmons was something of a phenomenon. Hired by ESPN in 2001 to write for their web site, first as the “Boston Sports Guy” and soon as just the “Sports Guy,” his was the first voice on a major sports site to write from a fan’s point of view. And a funny fan, at that. Simmons wrote about sports the way fans actually talk about sports and he did so with a looseness of style, not to mention column length, that was unique among big-platform sports writers.

It didn’t take long before word about him spread. I know I was a early evangelist, sending some of his earlier columns to more a few friends under subject headings like, “You’ve got to check this guy out!”

Upon seeing the success that came from have a columnist torpedo the idea that sports media was about “insiders” writing for “outsiders,” ESPN decided that there was no lesson to be learned there, and gingerly stepped away from that door. Instead of introducing a “New York Sports Guy” or “LA Sports Gal” or others, and seeing if they connected with readers like Simmons had, ESPN decided that, while Simmons would continue to do his thing, his situation would be unique.

With that decision, ESPN hasted the rise of the alternative sports blog scene, one that would bedevil them, by years; put itself in a more difficult situation in terms of talent negotiation; and made harder their current effort to generate revenue through locally-oriented content.

Make no mistake, Simmons is a talented writer and it’s admirable that, in an era when most sportswriters seems to view actually “writing” as a means to a radio show or regular television appearances, he takes it quite seriously. Simmons’ success, though, was also the result of his being the right kind of voice, at the right time, on the biggest platform imaginable.

A large part of the sports blog scene rose up in opposition to the relative stranglehold on sports media that ESPN had. Since the early 1990’s, The World Wide Leader (as it calls itself) decided what was newsworthy, what was interesting, and what was funny. And it presented a world where athletes didn’t swear; managers and coaches had to do something supremely dumb to be called mildly mistaken; and, for years, the only sports with steroid problems involved either the former Eastern Bloc or bike racing.

A roster of “outsider” writers, dealing with sports culture closer to the way normal humans do (though still without swears), would have seriously lessened the market’s hunger for sites in the vein of Deadspin, The Big Lead, and With Leather.

As it happens, one of that sports blog community’s favorite pastimes is reading the tea leaves about what Bill Simmons will do when his current contract with ESPN expires in 2010. He’s already, by my reckoning, more effectively monetized being a writer on the web than anyone else. There will be competition for his talents and who ever gets him will have to open up the piggy-bank. Meanwhile, ESPN hasn’t developed any voices that might be credibly able to take his place.

Another possibility, one that Simmons himself mentioned in an interview, is that he might start his own sports web site. The readership that he could take with him to such an enterprise would be significant, and with the low overhead of web journalism, I wouldn’t bet against him.

Finally, over the last year ESPN has launched several locally branded pages, such as ESPNBoston, to compete with local sports pages for readers and advertisers. If they’d used their experience Simmons as an example of how a local focus can be used as an incubator for talent, ESPN would already have writers with the experience and platform to bolster their local efforts. Instead, ESPN has to poach talent from the newspapers they’re competing with.

ESPN dealt with the success of Bill Simmons like an old media company.

When Bill Simmons succeeded, ESPN had discovered a new paradigm for sports media on the web, but was far more comfortable just deciding that they’d found a new star.

They’ll be paying for that mistake for quite some time.