Ars Technica: “As the result of a Freedom of Information Act request filed by the American Civil Liberties Union, the Department of Justice has revealed, for the first time, the types of secret letters that the government can send out to ISPs and other tech companies being asked to reveal personal data about their users and customers who are being investigated for national security reasons. In 2009, over 6,000 Americans received such National Security Letters (NSLs). According to the Wall Street Journal, the “letters show that the FBI is now informing people who receive the letters how they can challenge the documents in court. But some key elements of the letters remain blocked from view—including lists of material the FBI says companies can send in response to the letter.”