So, what next for "The Sopranos"?

That is the question facing HBO executives and the creative team behind the show as they ponder how best to seize the moment for a series that is now a cultural phenomenon on par with the most successful television programs of all time.

Especially tantalizing to its producers is the fact that "The Sopranos" is now attracting broadcast network-size ratings even though only a third of the nation's television audience subscribes to HBO, the pay-cable channel that reaches 30 million homes. Even at the start of the new television season, when "The Sopranos" faced premieres of series on the freely available broadcast networks, the HBO show has been overpowering network offerings on Sunday night.

Last week "The Sopranos" pulled in 11 million viewers, better than almost any other show on any channel that night. And its rating among the young adult viewers that the networks covet overwhelmed everything they had to offer.

HBO now has the first television megahit ever to be unavailable to the majority of viewers. And it is carefully calculating its future options. 

Officially, the show is to conclude at the end of next season, its fifth. But that plan may be changing. Executives are seriously discussing extending the show to a sixth season, though they acknowledge that it will entirely depend on the decision of the show's creator, David Chase. The show's cast, including its star, James Gandolfini, is already under contract for six seasons, if the producers decide to extend the show's run.

Another possibility, already discussed by Mr. Chase and HBO, is to bring the characters to the big screen in a post-series theatrical movie. That is under active consideration, people involved in the show said.

But HBO has another highly valuable property on its hands: 39 previous episodes of "The Sopranos" that were never available to the general television audience. While HBO has already reaped sizable profits from about a million DVD sales of the first season of "The Sopranos," as well as revenue from rental outlets for videocassettes of the first three seasons, these sales hardly exhaust the show's potential. For one thing, HBO executives point out that 60 percent of those sales went to HBO's subscribers, meaning the huge audience that never saw those episodes has hardly been dented.

HBO executives have a range of choices about how best to expand the market. The old episodes could, in theory, fetch enormous prices in syndication either from a basic cable network or local television stations, or perhaps even one of the broadcast networks.

All those possibilities would be complicated by issues like how commercials could be inserted, and even more daunting, how its unsparing language, violence, and sexual situations could be rendered acceptable on any of those far more content-sensitive outlets. But HBO has, from the beginning, produced alternate scenes with different language and other editing, specifically designed to make the show more palatable to mass-reach television outlets.

Both HBO and the show's creative team have expressed reluctance to do anything to capitalize financially on the show's success that would compromise its creative vision or put its reputation at risk. "There are no cavalier decisions made about `The Sopranos,' " said Bray Grey, one of the show's executive producers. "Creatively and on a business level, my guess is that won't change."

HBO's own research indicates the show is popular among every kind of audience group among its subscribers, leading the network to conclude that it would be just as potent a force among non-HBO viewers were it available to them.

But the exact degree of interest that exists beyond the HBO audience is unclear. Also unknown is how many viewers who do not subscribe to HBO are frustrated by being left out of the national discussion about what has become the most talked-about entertainment vehicle of the past five years.

"It's one of those things where I'm so sick of hearing people talk about it," said Jamil Azam, a graphic designer from Jersey City. Like other, non-HBO subscribers, Mr. Azam has heard all the talk and seen all the media coverage, but he does not watch the show, and he says, "I don't care."

Presumably, HBO could reach masses of new viewers if it decided to distribute "The Sopranos" on broadcast outlets. But Chris Albrecht, the chairman of HBO, said, "I don't feel obligated to America to find a way to get it into all homes."

In truth, he said, all the clamoring to see the show might be just as good an argument to keep "The Sopranos" as tightly held as possible for as long as possible. "When you think of our business, it makes sense for us to try to see it's only available on HBO, or products we distribute." The object of such a plan, of course, would be to help advance subscription sales, which are the lifeblood of HBO's business.

But curiously, the most powerful show HBO has ever owned has not been a force for driving up subscriptions to the channel. 

"The realities of pay TV have been changing," Mr. Albrecht said. "You have declines in cable penetration growth now." And, he added, HBO does not really have a direct relationship with its own subscribers because it is forced to go through a middleman: the cable-system operator.

"That means we're just part of everything else," he said. "First the consumer is asked to pay $60 for the basic cable service and then it's another $40 for the platinum package, and they're selling Showtime and Starz in with us."

Mr. Albrecht argued that HBO's inability to use "The Sopranos" to drive its revenues in a direct way was an example of a disadvantage of the pay-cable economic system, where advertising dollars are nonexistent.

"We always hear about how HBO has got the perfect economic model," he said. "But here we have a hit, and we don't have an easy way to directly monetize it. A network would take these ratings, go to the advertisers, up their rates and monetize it right away."

If HBO could market only its own channel, there might be a more direct financial benefit to be gleaned from having a hit like "The Sopranos," Mr. Albrecht said.

His point was backed up by one of those frustrated non-HBO subscribers who have been hearing about "The Sopranos" for three years. "I have to say, if there was a way I could get just HBO, I might actually go and bother to do that," said Joanne Landolcetta, a digital artist from Culver City, Calif. HBO is occasionally available à la carte on some cable systems — particularly those owned by HBO's parent, AOL Time Warner — but even when it is available, cable systems rarely market it that way, instead using it to drive bigger sales of premium channels.

For HBO, "The Sopranos" has an additional, notable strength — the show has burst into the national consciousness as an automatic cultural reference point, much like television hits of the distant and recent past, from "I Love Lucy," "Dragnet" and "Leave It to Beaver" to "Seinfeld," "ER" and "Friends."

Going back several decades, especially before the growth of cable fragmented the television audience, virtually all Americans could use television as a common connection in conversation, identifying the cloying phony dating their daughter as "Eddie Haskell reborn," or the bigoted ignoramus at the lunch counter as "Archie Bunker without the laughs." Now, at a cocktail party, you might hear that someone's older relative is reminiscent of Junior, Tony Soprano's uncle, or that a sleazy neighbor is as creepy as Ralphie Cifaretto.

But Mr. Grey, one of the show's producers, said its entry into the culture should probably not be compared with those of other television shows. A better analogy, he said, would be the path that a hugely popular motion picture takes into public discourse.

Citing perhaps the best thematic parallel possible, Mr. Grey described how the "The Godfather" began as a blockbuster theatrical release, but only a relatively small percentage of the population paid to see it.

"They were the first ones to share the experience," he said, and though it was discussed widely in the media, those who did not shell out to buy a ticket were left out of the chat.

Eventually, of course, "The Godfather" moved through what he called "the other windows of distribution," through videocassettes, cable channels and especially broadcast channels, and became seen all but universally.

"But a fair question would be whether those that saw it edited on television had the same cultural experience as those who saw it in the theater," Mr. Grey said.

He said he believed the creative staff behind "The Sopranos" feels like the show is "a very special thing," and that looking for ways to further capitalize on it might somehow jinx the experience.

"Maybe you just leave well enough alone," he said. "Enjoy the reception," he added, while sharing the sentiments of Carmela Soprano in the first episode this season: "Everything comes to an end."