In a strong display of unity, several large US tech firms have come to the defence of Facebook, as the social network contests a court order which required it to hand over users' data.
Google, Microsoft, Twitter and Dropbox are among those who have filed court documents arguing that the search warrant violated the US Constitution.
In June, Facebook revealed it had given a New York court the personal data of 381 people involved in a fraud trial.
Only 62 of those were later charged.
Photographs, private messages and other information were supplied by the social media site to the court in 2013, as part of an investigation into fraudulent claimants for US federal disability benefits.
The court said the defendants' Facebook accounts had contained evidence showing that they were, in fact, healthy.
The social media site, which had its initial appeal against the warrant denied, said the request was "by far the largest" it had ever received from a government body.
In documents filed to a New York court, and seen by the BBC, the following US tech firms threw their support behind Facebook:
Some of the companies argued that the process violated the First Amendment to the US Constitution, which protects freedom of speech, and the Fourth Amendment, which protects against "unreasonable searches and seizures" of persons' belongings.
In their submission to the court, firms such as Google and Microsoft said they had "a strong interest in the resolution of the issues in this case", as they too faced similar legal battles over the protection of user data.
A lawyer representing some of the medium-sized firms, including Foursquare and Tumblr, expressed concern that "smaller entities, such as start-ups and other developing companies, may not always have the resources to litigate," when confronted with a government search warrant.
But the firms were most angered by the fact that the entire proceedings had been kept private by the court.
Two months ago, Facebook revealed that the US government had obtained "gag orders" to prevent it from telling the account holders that their data had been passed to prosecutors.
The story was only revealed almost a year later, after a New York judge agreed to make the process public.
The tech firms rallying behind Facebook said it was "far from clear" that the order had served a compelling government interest.
A separate filing was made by both the New York and American Civil Liberties Unions, who outlined their opposition to the court's decision, warning that "Facebook users are at risk of dilution of their constitutional rights".