When companies receive National Security Letters (NSLs) from the FBI or a FISA (Foreign Intelligence Surveillance Act) request from the NSA, they also get a gag order barring them from telling anyone. There is one way that websites can inform users that they've been subpoena'd without breaking the law, though: Using a "warrant canary." Those are simply statements in transparent reports that indicate a site has not received a letter since a certain date. Reddit had one in its 2014 report (below), meaning it had never received a subpoena as of January 29th, 2015. Last year's report, released yesterday, includes no such remark, meaning that the company did indeed receive the dreaded letter sometime last year.