KANSAS CITY, Mo. — Young voters are on a roll this election season. They rolled right through Super Tuesday in record-breaking numbers and are poised for a remarkable, maybe election-altering, turnout in November.

"This is an entirely new generation of young people," said Heather Smith of Rock the Vote, a nationwide advocacy group. "They're finding their voice in the political process now and realizing that when they do turn out, campaigns pay attention to them."

The potential clout of younger voters has long been ballyhooed. The numbers show they might finally be cashing in, politically.

Voter turnout tripled among young voters in the Missouri primary, according to a University of Maryland research center. That's compared with the 2000 presidential primary, the last time similar data was available.

Nearly 191,000 young voters cast ballots in the state on Super Tuesday, compared with 71,000 in the 2000 primary. Turnout among young people was a woeful 7 percent in 2000 and hit 21 percent last week.

The numbers — and the zeal — are expected to grow through the November election.

Smith said Rock the Vote helped register a half-million young voters in preparation for Super Tuesday and is on track to register more than 2 million this year. Most will vote in November, she said.

So far, young voters are playing a strong part in the narrative of this presidential primary season, a trend that started in 2004. Youth voter turnout had declined in all but one presidential election year between 1972, when 18-year-olds first voted and 2000.

"In 2004, something changed," said Emily Kirby, of the Center for Information & Research on Civic Learning & Engagement. "And again in 2006. Now we're seeing this a third time with the primaries and caucuses."

On Super Tuesday, the "youth vote" also tripled in Georgia and Oklahoma and quadrupled in Tennessee, Kirby said. Earlier, Florida and Iowa also saw a tripling in youth turnout, although not every state has had increases. Kirby said her center can't crunch numbers from the Kansas Democratic caucus Tuesday or Saturday's Republican caucus because of a lack of exit poll information.

Technology — specifically the ease and allure of the Internet — is part of what's fueling participation.

Meghan Whelan of Kansas City, Kan., did her part in upping the numbers, and she doesn't plan to stop now. She's a Barack Obama supporter and is using her MySpace page to keep 240 "friends" informed.

"It's my own MySpace campaign," said Whelan, 26. "I talk about how Barack Obama inspires me and how we need to show people that as young voters we do care, that we need to go against the stereotypes."

Then there was the YouTube video called "Yes We Can," a musical adaptation of an Obama speech. Made by a member of the Black Eyed Peas, the video has been watched more than 2 million times in the last week.

"It was really powerful, so I made sure I put it up for everybody to watch," Whelan said. "We don't necessarily have the money to donate, but we can put time and energy into this."

Nathan Lipsky, 17, was one of hundreds of Kansans waiting in line Saturday to get into the Republican caucus at the Matt Ross Community Center in Overland Park. He is eligible to vote because he will be 18 come Election Day in November.

His choice: John McCain.

"I like his stand on foreign policy, and I think he's the best candidate for the party," said Lipsky.

The 18-to-29-year-olds have something else: a big — and growing — head count.

The year 1990 marked the highest number of births since the baby boom, which officially began in 1946, and those babies are turning 18 this year. Some 44 million people between 18 and 29 are eligible to vote in 2008, according to Rock the Vote, the young voter advocacy group.

"That's nearly a quarter of the electorate," said Smith, executive director, "and there's a huge surge just waiting at the gates. By 2012, it will be nearly a third of the electorate."

The strength of the youth vote is tipping elections, she said. An estimated 70,000 young voters cast ballots for Obama in Missouri's Democratic primary, which he won by just 10,000 votes.

Besides online factors — social networking sites, blogs, candidate Web sites, YouTube and so on — here are some of the reasons experts cited for increases in youth voting:

—In the 2004 election, campaigns began hiring youth directors, who were charged with pursuing this untapped pool of voters.

—Campaigns altered tactics, using more canvassing and other one-on-one appeals. Research shows that the more personal the appeal the better, especially when one young voter contacts another.

—Contested elections feel more important, especially to young voters who are more likely to question whether their votes matter.

—This year's issues seem particularly relevant to young voters. In a recent Time poll, 75 percent of under-30 Americans felt the country was going in the wrong direction, with particular concern about jobs, health-care affordability and the war in Iraq.

—Obama is attracting young voters. In most states so far this primary season, Obama has outpolled Hillary Clinton among young voters.

Mary Opie, who was a Romney supporter and now undecided, said the wide-open race and the weight of current issues are drawing in the under-30 crowd.

"After a president who's been in for eight years, we're starting over; it's anybody's game," said Opie, 28. "And with the war, the life issues, the Supreme Court appointments, there's a lot at stake. Especially with the war, I feel that if there are people willing to put their lives on the line, I feel I need to do what I can to contribute."