Growing at a rate of roughly 30 percent a year, BAM now takes in about $400 million in revenue. Going by its logs, it entertains more than 50 million visitors a month, putting it close to the top 100 sites of any kind. By the end of the season, more than a million subscribers will pay for its media offerings, including video content of all out-of-market games at $99 to $120 a season and audio broadcasts for $20 a season. More than a billion minutes of baseball will flow from its servers. It sells more than $80 million in merchandise, ranging from hats and jerseys to authenticated relics like signed baseballs and bases. (In the 24 hours after Boston became champs in 2004, the site sold $5 million worth of Red Sox gear.) BAM processes a third of the 75 million tickets sold for major-league parks, and resells at premium prices the ducats that season-ticket holders want to offload. It also employs a team of journalists who cover each team—"we had to make sure our reporters were independent," says BAM's content czar Dinn Mann—and hosts hundreds of blogs written by players, celebrities and fans. One of the fastest-growing revenue streams is advertising, now bringing in 15 percent of the total. . . .

BAM's success—as well as the egalitarian structure of its ownership scheme—has deep implications for the sport's future. Because each of the 30 clubs has an equal share, BAM is a Trojan horse for parity in a game where the payrolls of some teams (well, one) is eight times that of the financial cellar dwellers. In other words, the mighty New York Yankees' share of the pie is no bigger than that of the hapless Tampa Bay Devil Rays.