Craigslist, is facing accusations that it has become a hub for underage prostitution after two young women placed an advertisement in the Washington Post saying they were repeatedly sold through the site to men who "paid to rape" them. The allegations came as a federal judge threw out an attempt by Craigslist…to stop a criminal investigation over its "adult services" section which is alleged to carry thousands of prostitution ads daily…The ad was partly paid for by Fair Fund, a group working with young women who have been sold for sex. It described Craigslist as "the Wal-Mart of online sex trafficking"…Craigslist's chief executive, Jim Buckmaster, said it worked tirelessly with law enforcement agencies to identify ads that exploited children, manually reviewed every adult service ad before posting and required phone verification by the person placing it.