This is super-scary.
“[T]he 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”
The Electronic Frontier Foundation took the case pro bono and, when the website operator refused to just hand over the information, the DOJ just backed down. Which implies that they were attempting to strong-arm someone into handing over information they had no legal right to. Read the EFF’s whitepaper (long) or blog post (shorter) about the case.