LinkedIn has joined Yahoo! and Google in lobbying the US government to let it tell the public how many super-secret requests from spies it gets for user data.

The career network said on Tuesday that it has filed a legal challenge with the US government to let it be more open about the number of spy requests – "National Security Letters" or Foreign Intelligence Surveillance Court (FISC) requests – it gets for the info of denizens of its network.

LinkedIn announced its attempt at broader disclosure alongside the publication of its semiannual Transparency Report.

From January 1 to June 30 of this year, LinkedIn received 83 Government requests for user data, 70 of which came from the US and 4 from the UK. It provided data for 57 per cent of the US government requests, and none for those from the UK. This compares with 48 requests for user data in the second half of 2012, 67 in the first half, and 73 in the second half of 2011.

This report excludes requests related to US national security, as these info requests are so secret that the company is not permitted to disclose them.

"We have been expressly prohibited by the U.S. government from disclosing the number of U.S. national security–related requests we receive, if any," LinkedIn's general counsel Erika Rottenberg, wrote. "This prohibition, which limits our ability to provide the transparency that we think our members and the public deserve, has been the source of great disappointment and frustration to us."

To spur disclosure, the company has filed an amicus brief in the US Court of Appeals for the Ninth Circuit that urges it to affirm that National Security Letters (NSL) violate the First Amendment.

It has also filed a petition with Big Brother the Foreign Intelligence Surveillance Court asking permission to public information on these letters.

At the moment, the Federal government is saying LinkedIn can disclose the number of letters it gets in batches of 1,000. As the site points out, given the hundred-ish requests it got from governments for data last year, the sudden appearance of a bucket for "0 to 1000 NSL requests" bucket might freak out members.

"We believe that this type of reporting defeats transparency, and in fact, would be misleading about the number of users affected by government requests, and could generate unwarranted concern by members and the general public, both in the United States and abroad."

With the petition and amicus brief, LinkedIn is following in the footsteps of Yahoo!, which lodged a similar appeal with FISA in July, 2013, and Google which did the same in June.

But given the interlocking layers of secrecy involved in processes like this, it's doubtful that these companies will ever be able to tell us how their negotiations are progressing. ®