Until recently the US Government was issuing tech companies National Security Letters (different from subpoenas, they do not require judicial approval) and the

Until recently the US Government was issuing tech companies National Security Letters (different from subpoenas, they do not require judicial approval) and the letters had built in gag orders. In other words if the recipient could not discuss what was being requested by the government, or even challenge the request in court without criminal penalties. Recently courts have reviewed this and given a partial lift on the built in gag orders. (see: http://en.wikipedia.org/wiki/National_security_letter http://en.wikipedia.org/wiki/National_security_letter)