U.S. Democratic party candidates squared off on Monday, answering questions from people who posted their queries on YouTube about Iraq, the military draft and their role in a broken political system.

In an effort to energize the debate format, thousands of Americans uploaded their questions to YouTube, the video sharing site, for the two-hour debate on Monday evening in Charleston, South Carolina.

"Wassup?" was the first question, from a voter named Zach, whose video got the debate, sponsored by Google-owned YouTube and CNN, off to an unconventional start. He went on to ask how any of the Democrats would do better than the failed leadership in Congress and the White House.

"How are you going to be any different?"

Trying to appeal to the public's thirst for change, Illinois Senator Barack Obama replied, "One of the things I bring is a perspective … that says Washington has to change."

His chief rival of the eight candidates in attendance, New York Senator Hillary Rodham Clinton, claimed she has a 35-year-record as an agent of change.

"The issue is which one of us will be ready from Day 1."

CNN editors chose about 25 questions from more than 2,000 videos that were posted on YouTube for the debate, which was the 2008 campaign's fourth event. The candidates faced some blunt questions, some earnest and ridiculous ones that were responded in kind.

One person asked Obama: Are you black enough?

"You know, when I'm catching a cab in Manhattan … in the past, I think I've given my credentials," he replied.

Another asked Clinton: Are you feminine enough?

"I couldn't run as anything other than a woman," she said.

Her response was met by a challenge from former North Carolina senator John Edwards, who said he was the best advocate for women among the candidates.

"I have the strongest, boldest ideas," he said.

Some of the submitted videos were posted before the debate began, with topics including the Iraq war, health care, Darfur, education, immigration, gay rights and the environment

"Will you send your children to public school?" asked one woman.

One woman who identified herself as Kim, a 36-year-old breast cancer patient, began her question by taking off her wig. She said she hoped to be a future breast cancer survivor, but her chances weren't good, because she, like millions of Americans, had gone for years without health insurance that would have allowed her to take preventive medicine.

But some questions took on a less serious tone. At the beginning of last week, the most watched video question was someone asking if California Gov. Arnold Schwarzenegger was a cyborg.

"Eighty-eight per cent of Californians elected Gov. Schwarzenegger in hopes that a cyborg of his nature could stop a future nuclear war," the man said.

In midweek, the most popular question was if President George W. Bush should be impeached.

A woman from Ajax, Ont., also posed a question, asking how the candidates would improve Canada-U.S. relations.

With files from the Associated Press