The danger of the sites is they are open to response and therefore criticism that could backfire in the candidate's face in the run-up to the Nov. 7 midterm elections, the newspaper said.
For example, on the Facebook site, the page for Sen. Hillary Clinton, D-N.Y., is sprinkled liberally with posts from her Green Party rival, Howie Hawkins.
On a YouTube page for Rep. Ron Kind, D-Wis., his Republican challenger, Paul Nelson alleges Kind voted to fund studies of "the sex lives of Vietnamese prostitutes," although Kind's campaign manager told the newspaper said he was confident voters would "see through these kinds of sleaze ads."
MySpace has 56 million visitors a month and spokesman Jeff Berman told USA Today that visits to political pages have surged this year.
"When you can reach people that quickly, that effectively and at no cost, it's just a no-brainer," he told the newspaper.