ABC News arrived at the future here Monday night, but Sam Donaldson was left behind.

He couldn't hear anything.

"I have no patience!" he declared as the roar of the FleetCenter crowd behind him drowned out the faint signal in his earpiece. "I have no tolerance, which is why I'm thoroughly disliked at ABC News!" he said in self-mocking outrage. Through gritted teeth, he shouted: "I want to kill!"

ABC cut to Matthew Greenberg, a bearded man in a blue work shirt and white T-shirt sitting at a laptop. The programming director of AOL News read from a flood of questions being submitted by America Online subscribers.

Most people didn't see the 7 p.m. program, which wasn't carried on the airwaves. It was available only online (to AOL, ABC News and RealNetworks subscribers), on digital television and on Sprint cell phones. ABC, which has no cable network, is offering 24/7 coverage of news and politics -- but only to those at the other end of a narrow technological pipeline.

Which raises the obvious question: If ABC's multimillionaire anchors and correspondents are troubling themselves to provide gavel-to-gavel coverage, why offer only three broadcast hours over four nights? "The American people have told us pretty resoundingly -- four, eight, 12 years ago -- they would rather do other things with their time than watch gavel-to-gavel coverage in the tens of millions," said ABC News President David Westin.

Or as Donaldson, holding a mike in a skybox as the arena echoed with the sound of Sly and the Family Stone, paraphrased Churchill: "Never have so many covered so little for so few."

For AOL, the joint venture is a matter of "doing what we do best: providing interactive programming for our 24 million members," said spokesman Brian Hoyt.

ABC News Now was launched last year on the Web and with Comcast digital networks. Between now and the election, many ABC affiliates, including Washington's WJLA, are offering the coverage on their separate digital channels, available only to those with specially equipped TVs -- enough to reach 60 percent of the nation's markets.

The 7 p.m. show would end up being seen by about 210,000 AOL subscribers, which left company officials ecstatic and surpassed the streaming video of a Dave Matthews concert. In television terms, however, that is a minuscule payoff, but there was little grumbling among the ABC troops about the extra work. "It's like oxygen," said one network staffer. "These guys love to be on the air."

Monday's program began crisply enough, with anchor Hari Sreenivasan in New York tossing questions at Donaldson and ABC political director Mark Halperin. But as Donaldson was talking about Bill Clinton's popularity among Democrats, the sound problems began. Viewers have little idea how hard it is to have a conversation through a tiny earpiece called an IFB in the midst of a deafening basketball arena.

"I hear you, but barely," Donaldson said. "There's a huge noise in here."

So Greenberg got more air time than expected. "In the last 20 minutes, 1,500 messages have come in, and a majority of them are about the Clintons," he said. As for John Kerry and John Edwards, "there still seem to be a lot of people, at least in AOL world, who are wondering what can I learn about these candidates. . . . Interestingly, I haven't gotten a single question about [Al] Gore."

"He's yesterday's news," Donaldson said. But the earpieces soon went dead again, leaving Halperin tapping out BlackBerry messages while the program reran a Charlie Gibson interview with Hillary Rodham Clinton.

In a cramped studio on another floor, Peter Jennings, in shirtsleeves, was getting ready to go live at 8 p.m. He will anchor more than 27 hours from Boston.

"It's interesting," Jennings said of the narrowcasting experiment. "I don't know who's watching it or listening to it or reading it. I find myself talking as if it's an international audience," since AOL users around the world can access it, "taking less for granted about what we're doing here.

"There's a measure of spontaneity you get with this that is very refreshing. You remember people are looking at snippets of this. They're not glued to their computers or their cell phones."

ABC is also trying to lighten up. The show, Jennings noted, would open with Jimi Hendrix music.

In walked the first guest, Howard Dean. "I'm sorry you won't be camped out in Burlington," the former Vermont governor said, referring to the expectation of just six months ago that he would be giving the acceptance speech here. Jennings couldn't hear him -- he had an earpiece in each ear -- and had to take one out to say hello.

Dean seemed unsure about what they were doing. "So this is what, on the Net?" he asked.

It was a bittersweet moment, for Jennings had only three or four minutes before Gore took the podium. So Dean, the would-be nominee, was acting as filler before a speech by the would-be president in a conversation with one of America's most prominent anchors that would be seen by a fraction of his usual audience.

Dean said his candidacy had been "incredibly liberating" for the Democratic Party by demonstrating that "it's not unpatriotic to criticize the president of the United States." When Jennings turned to the camera and began setting up Gore's speech, Dean smiled and excused himself.

Jennings, for his part, spoke for two more hours to the digital nation until ABC's cameras began beaming him to the rest of the country at 10 p.m.

Ted Koppel reports from the convention floor for ABC News. Much of its coverage is available only on ABC News Now, launched last year on the Web and available through a variety of digital media.