With that, Kay was finally able to shut him down. “Over the line,” he said. “And I’m speaking as your publicist, not as a Laker fan.”

For Simmons, this distinction — between fan and columnist — doesn’t really exist. Unlike many sportswriters, for whom detachment is a point of professional pride, Simmons makes no pretense of neutrality. This is at least one explanation for his extraordinary popularity. According to ComScore, Simmons’s “Sports Guy” Web column, which he publishes every 10 days or so, attracted 740,000 unique visitors in April, making him probably the most widely read sportswriter in America today. The column is just one of several media through which Simmons connects with his fans. He has written two best-selling books, the first a memoir of Red Sox fandom, the second a popular history of the N.B.A. His regular podcasts, “The B.S. Report,” are downloaded an average of 600,000 times each.

Later this month, Simmons will take another step in the ongoing expansion of his empire, starting his own Web site, in conjunction with ESPN, called Grantland. Simmons says Grantland will be to ESPN what Miramax was to Disney, a boutique division with more room for creativity. Another metaphor might be Martha Stewart Living, a magazine similarly constructed around a single person’s market-tested sensibility. Much has been made of some of the well-known, literary writers Simmons has already attracted to Grantland, but as a business proposition, the site is basically an attempt to leverage Simmons’s take on sports and, really, life into something much bigger than himself.

After the game, Simmons, still feeling festive, led a group to a nearby sushi place for a nightcap. “Let’s sit outside,” he proposed. “I want to see the faces of the sad Laker fans walking by.”

A brief, reductive history of modern sportswriting in America might look something like this: Practitioners of the craft during the first two-thirds of the 20th century paid for their unfettered access to athletes by glorifying them, “Godding up those ballplayers,” as one sportswriter memorably put it. In the 1970s, sportswriters stopped protecting athletes and started demythologizing them. As they did, their access diminished. The gulf between ballplayers and fans widened.

Enter Simmons and his legion of imitators, whom you won’t find loitering in a locker room, trawling for quotes or sitting at the press tables of an N.B.A. game, where rooting is forbidden. At the center of Simmons’s columns is not the increasingly unknowable athlete but the experience of the fan. His frame of reference is himself. He might not be able to tell you how a ballplayer felt performing a particular feat, but he can tell you how he felt watching it, what childhood memories it evoked, the scene from the movie “Point Break” it brought to mind, which one of his countless theories — newcomers to his column can consult a glossary on his home page — it vindicates. There’s a vaguely metaphysical quality to this approach: the sportswriter Robert Lipsyte calls it “the tao of Bill.”

Simmons is more than just a fan; he is the fan, the voice of the citizenry of sports nation. In a larger sense, what he’s doing is nothing new. In much the same way that newspaper columnists call out callous politicians and crooked businessmen, Simmons rails against greedy owners, the commissioners who invariably side with them, overpaid players and dysfunctional franchises. Recently, he lambasted the Maloof brothers, the owners of the Sacramento Kings, for neglecting the team, and David Stern, the N.B.A.’s commissioner, for allowing them to do so. “Once you get approved to purchase an N.B.A. franchise, for whatever reason, David Stern seemingly yields all control over your behavior unless you criticize his officials,” Simmons wrote. “Anything else? Knock yourself out. Buying into the N.B.A. is like buying a house: Once you move in, feel free to disgrace the neighborhood however you want.”