LAS VEGAS – Could these laptop-strewn hotel hallways be the 21st-century equivalent of the smoke-filled rooms of yesteryear?

The largest-ever gathering of liberal bloggers, which got underway at a hotel on the Las Vegas Strip yesterday, is attracting a parade of Democratic Party leaders and potential 2008 presidential candidates, convinced that the so-called netroots have become a political force too powerful to be ignored.

“People realize the Internet is changing the game and the blogosphere is part of that,” the conference’s lead organizer, Gina Cooper, told The New York Sun.

About 1,000 bloggers from across the country are expected to attend the four-day event, dubbed YearlyKos, after the Web’s most popular liberal blog, DailyKos.com.

Ms. Cooper, 36, a former high school teacher from Sonoma County, Calif., said Democratic politicians aware of the Web-as-kingmaker buzz have been clamoring to grab speaking slots. “People want that netroots branding, and who can blame them,” she said.

Senate Minority Leader Reid, Senator Boxer of California, and the chairman of the Democratic Party, Howard Dean, all plan speeches to the online activists. The House minority leader, Nancy Pelosi of California, was also to attend but canceled due to an expected vote, Ms. Cooper said.

Among potential 2008 presidential candidates, the most concerted attempt to win over the liberal netroots is coming from a former Virginia governor, Mark Warner. He is scheduled to speak to a conference-wide lunch on Saturday and has invited attendees to a “Blogosphere at the Stratosphere” party, that will feature an open bar, free food, and free roller-coaster rides.

Three other possible presidential contenders have signed up to address smaller breakout sessions. A former energy secretary, Governor Richardson of New Mexico, is to talk about energy issues. Governor Vilsack of Iowa is part of a panel discussing education. A former general who mounted a presidential bid in 2004, Wesley Clark, is to take part in a science-related forum.

Notably absent is the presumptive Democratic front-runner in 2008, Senator Clinton. Senator Kerry, who won the nomination in 2004 and is considering trying again in 2008, also took a pass.

Spokesmen for Mrs. Clinton did not respond to questions about her absence.

A spokeswoman for Mr. Kerry, April Boyd, said her boss would have liked to be present, but had previous obligations. “He’s way into the netroots. He just posted something on the Huffington Post,” Ms. Boyd said.

A political consultant credited with harnessing the power of the Internet to propel Dr. Dean’s 2004 presidential campaign, Joseph Trippi, said Mrs. Clinton was making a mistake by overlooking the event. “Not paying attention to what’s happening here is almost like not paying attention to Iowa,” he said, referring to the pivotal role played by the rural state’s early caucus. “I think 1,000 bloggers is pretty impressive. If there were 1,000 reporters here, you know Hillary would be here.”

Mr. Trippi noted that DailyKos and other sites get a million or more page views a day. “We have a bigger readership than the New York Times combined,” he said. Still, the veteran political organizer said, candidates and campaigns are struggling to figure out how to deal with the blogosphere.

“Some politicians and press secretaries have no problem returning the New York Times’s phone call but wouldn’t think of answering an e-mail question from a blog,” he said.

The Dean campaign, which brought in $59 million through the Internet, proved the money-raising potential of the Web. Until recently, the ability of Web activists to deliver substantial numbers of votes has been unclear. But attendees at the YearlyKos event point to early signs of success. On Tuesday, an organic farmer and butcher, Jon Tester, won a Democratic Senate primary in Montana, thanks in large part to support from bloggers. Another major test will come in Connecticut in August when a anti-war challenger with strong backing from the netroots, Ned Lamont, squares off with Senator Lieberman in the Democratic primary.

Whether bloggers can wield much influence in general elections remains an open question.

“The Web’s not big enough to push a candidate over the top right now,” Mr. Warner’s Web guru, Jerome Armstrong, acknowledged. “The Internet has gotten to the point where it’s a really important factor early on.”

One challenge facing potential presidential candidates like Mr. Warner and Mrs. Clinton is that many Democratic blogs are replete with criticism of any politician perceived to stray from traditional liberal dogma on issues like abortion and the war in Iraq. Forming too close a bond with the blog world could pull a candidate into positions that might alienate less partisan voters.

Mr. Armstrong, who founded a popular liberal site, MyDD.com, and worked on the Dean campaign, took issue with the perception that most bloggers are ideological purists.

“I don’t think the netroots are homogenous. I think there’s definitely a pragmatic strain,” said Mr. Armstrong. He recently joined with the founder of DailyKos, Markos Moulitsas Zuniga, to write a book, “Crashing the Gates,” which describes how Internet activists can wield influence in American politics.

While the Bush administration remains the number one target of liberal bloggers, some, including Mr. Moulitsas, train a surprising amount of fire on perceived turncoats in the Democratic Party. Great vitriol has been directed at a centrist group once headed by President Clinton, the Democratic Leadership Council.

Last month, Mr. Moulitsas told an online magazine,Salon.com, that he had decided to stop bashing the centrist group. “I realized the more I talked about them the more relevant they became,” he said.

It did not take long for the DailyKos founder to fall off the wagon. “The DLC is an irrelevant, dying organization. Because it has no people behind it,” he wrote Wednesday in a post touting victories of liberal Democratic candidates in primaries in California and Montana. “It has no natural constituency. No ability to mobilize anything more than corporate lobbyists for any cause.”

“The DLC is dead. It might not know it yet,” Mr. Moulitsas continued, while adding, “Our job isn’t to obsess over that organization’s doings.” A spokeswoman for the Democratic Leadership Council, Tammy Sun, said the organization was taking Mr. Moulitsas’s latest salvo in stride. “Been there. Survived that,” she said.

Mr. Trippi said the council has also fueled the conflict. “They’ve made comments that bloggers are like the bar scene out of Star Wars,” he said. “It’s a two way street.”

The consultant acknowledged, however, that the tirades common to the blogosphere can be offputting. “I’m not pure enough for some of these people,” he said.

Mr. Trippi said politics on the Web remains in its infancy and that the forays bloggers are making into real-world organizing will have a moderating effect on the ideological inflexibility that prevails in much of the blogosphere. “It’ll get more mature and pragmatic, and, I think, smarter,” he said. “As you get involved in politics, you see you have to set aside a little of what you want to get votes.”