"In a case that raises questions about online journalism and privacy rights, the U.S. Department of Justice sent a formal request to an independent news site ordering it to provide details of all reader visits on a certain day. The grand jury subpoena also required the Philadelphia-based Indymedia.us Web site 'not to disclose the existence of this request' unless authorized by the Justice Department, a gag order that presents an unusual quandary for any news organization. ... Making this investigation more mysterious is that Indymedia.us is an aggregation site, meaning articles that appear on it were published somewhere else first, and there's no hint about what sparked the criminal probe."