The FBI can currently compel production of information on American civilians through the use of a "National Security Letter". This allows the FBI to skip the judicial side of things such as a subpoena and go straight to the source with few protections.
Worse yet, recipients of a National Security Letter are placed under an immediate gag order. They are to absolutely not speak to anyone about the NSL, or even mention it exists. This means that a company that provides you services would be prohibited from telling you that your information is being produced. Further, due to the Patriot Act, NSL's can be issued for people who aren't even suspected of a crime!
The Justice Department originally noted in a report that there had been abuse of NSL's by the FBI. The Electronic Frontier Foundation then filed a Freedom of Information request for data to be turned over, which was ignored. The EFF then filed the lawsuit which led to this ruling.
The thought of multiple government agencies all spying on American citizens with no judicial oversight and seemingly unending immunity scares me. It'll be interesting to see what the full extent of these abuses was (and is) when the letters are made available.