Four US presidential hopefuls - two Democrats and two Republicans - have taken part in an event aimed at young voters, presented on TV and online.
Facebook and MySpace sites have been key in generating support
The live forum was aired on the music channel MTV as well as on more than 1,800 websites and radio stations.
Democrats Hillary Clinton and Barack Obama appeared via satellite along with Republicans Mike Huckabee and Ron Paul.
Meanwhile Republicans across Maine have voted in weekend caucuses which former Massachusetts governor Mitt Romney won.
Mr Romney won just over half of the vote in the state caucuses, well clear of his main rival and current Republican front runner, John McCain, who won 20%.
The pair were trailed by fellow Republican candidates Ron Paul and Mike Huckabee.
The nonbinding votes are the first step in a longer process toward electing 18 Maine delegates to the Republican National Convention.
Maine's Democrats will hold their caucuses a week later.
The contest to become presidential candidate has been getting more tense ahead of votes in 24 states on "Super Tuesday" next week.
The MTV debate, designed to appeal to young voters, was also sponsored by the Associated Press and the popular MySpace website.
The candidates joined the 90-minute event via satellite - Mrs Clinton from Arizona, Mr Obama from Minneapolis, Mr Huckabee from Alabama and Mr Paul from Texas.
Although Mr Paul is not considered a front-runner to take his party's nomination, he has a huge online following.
Better polling Republicans John McCain and Mitt Romney declined to participate in the event.
Questions came from presenters in MTV's Times Square studio and from online and in-studio participants.
Speaking in the forum, Mr Obama said that his multicultural heritage allows him to "see through the eyes of other people" abroad in ways another president could not.
"If I convene a meeting of Muslim leaders to try to bridge the divide between Islam and the West, I do so with the credibility of someone who lived in a Muslim country for four years when I was a child," he said, referring to time spent in Indonesia.
"And although I'm a Christian I have a sense of that culture."
However, he was insistent that the contest was about much more than the race of the candidates, saying that if that were not the case: "I wouldn't have to answer questions. I could just show up."
Mrs Clinton said that both her and Mr Obama's presence in the contest represented "a sea change in America".
"Whichever of us gets the nomination, we are making history," she said.
Mr Huckabee, who opened the forum, complained that he always gets asked "the God questions", saying that "it's really been frustrating" that there isn't more focus on his political work.
Mr Paul answered a question on whether the US should intervene to end the violence in Sudan's Darfur region.
"I don't believe in using force in that manner," he said. "Under the Constitution, we're not allowed to do that."
Mr Obama has had the greatest success attracting youthful voters so far - and has a substantial following on social networking sites MySpace, Facebook and YouTube.
In South Carolina he won 70% of the votes of those between 25 and 29, but only 51% of those between 50 and 65. Mrs Clinton won more votes among retired people.
For Americans aged between 18 and 29, the web has become the leading source of campaign news.
However young voters make up only a small proportion of eligible voters and have a lower rate of participation.