YouTube as a Platform for Political Debate.

Media convergence is the merging an old form of media with a new form, that is, newspapers with the Internet.

By late last week, more than 1,700 videos had been put on YouTube's site for today's debate among Democratic candidates. The Republican debate will be on Sept. 17.

A political team at CNN will pick some 25 to 30 of the questions for the two-hour debate. Moderator Anderson Cooper may also ask follow-up questions.

Questions ranged from health care, Social Security, and global warming to U.S. foreign policy. Some are serious, and others are not. One man played a guitar and sang a song about the candidates' choice as running mates for vice president.

CNN political director Sam Feist said the network decided to hold a YouTube debate in part to highlight the enormous impact the Internet has on politics. "Clearly the YouTube phenomenon is the perfect opportunity to merge new media and old media in a presidential debate," he said, adding that the unpredictable nature of the questions will make it harder for candidates to prepare.

Feist said the questions were asked by a diverse group of people -- of all ages and from across the country and several foreign nations. He said he was surprised by the quality of the questions and that there were not more about the Iraq war.