Twitter is standing up for one of its users and challenging a court order to hand over his data.
Malcolm Harris, along with many others, is being prosecuted for disorderly conduct related to an Occupy Wall Street protest on the Brooklyn Bridge last year.
Twitter was ordered to hand over Harris's basic user information and the contents of his tweets between September 15 and December 31, apparently to disprove a potential defense that Harris was actually led on to the bridge by police in the first place.
But following Harris's failure to get the subpoena quashed, Twitter has leapt to his defence. It's filed a motion pointing out that its terms of service promise users: "You retain your rights to any Content you submit, post or display on or through the Services."
Twitter says the Stored Communications Act allows users to challenge demands for their account records; and in any case, it says, the Act is unconstitutional as it allows the disclosure of information without a search warrant.
Twitter's move has been welcomed by the American Civil Liberties Union (ACLU).
"This is a big deal. Law enforcement agencies — both the federal government and state and city entities — are becoming increasingly aggressive in their attempts to obtain information about what people are doing on the internet," says Aden Fine, senior staff attorney for the ACLU's Speech, Privacy and Technology Project.
"And while the individual internet users can try to defend their rights in the rare circumstances in which they find out about the requests before their information is turned over, that may not be enough."