In an unprecedented win for transparency, yesterday Google began publishing generalized information about the number of National Security Letters that the company received in the past year as well as the total number of user accounts affected by those requests. Of all the dangerous government surveillance powers that were expanded by the USA PATRIOT Act, the National Security Letter (NSL) power provided by five statutory provisions is one of the most frightening and invasive. These letters--the type served on communications service providers such as phone companies and ISPs and are authorized by 18 U.S.C. 2709--allow the FBI to secretly demand data about ordinary American citizens' private communications and Internet activity without any prior judicial review. To make matters worse, recipients of NSLs are subject to gag orders that forbid them from ever revealing the letters' existence to anyone.