The data is used as “part of immigration enforcement” which might be worth remembering if you ever want to go to the US on holiday.

A new cache of documents reviewed by 404 Media said that GOST operates under a chilling catchphrase “we see the people behind the data" and a user guide included in the documents says GOST is "capable of providing behavioural-based internet search capabilities.

Screenshots show analysts can search the system with identifiers such as name, address, email address, and country of citizenship.

After a search, GOST provides a "ranking" from zero to 100 on what it thinks is relevant to the user's mission. The documents further explain that an applicant's "potentially derogatory social media can be reviewed within the interface."

After clicking on a specific person, analysts can review images collected from social media or elsewhere and give them a "thumbs up" or "thumbs down."

Analysts can review the target's social media profiles themselves too, and their "social graph," potentially showing their social connections.

DHS has used GOST since 2014, according to a page of the user guide. ICE has paid Giant Oak Inc., the company behind the system, in more than $10 million since 2017, according to public procurement records.

According to the records, a Giant Oak and DHS contract ended in August 2022. Records also show Customs and Border Protection (CBP), the Drug Enforcement Administration (DEA), the State Department, the Air Force, and the Bureau of the Fiscal Service, which is part of the US Treasury, have all paid for Giant Oak services over the last nearly ten years.

The FOIA documents specifically discuss Giant Oak's use as part of an earlier 2016 pilot called the "HSI [Homeland Security Investigations] PATRIOT Social Media Pilot Programme." For this, the program would "target potential overstay violators from particular visa issuance Posts located in countries of concern."

Deputy Director of the ACLU's National Security Project, Patrick Toomey, said that the government should not use algorithms to scrutinise our social media posts and decide which of us is 'risky.'

“Agencies certainly shouldn't be buying this kind of black box technology in secret without any accountability. DHS needs to explain to the public how its systems determine whether someone is a 'risk' or not, and what happens to the people whose online posts are flagged by its algorithms,", he said.

The documents come from a Freedom of Information Act (FOIA) lawsuit brought by both the ACLU and the ACLU of Northern California. Toomey from the ACLU then shared the documents with 404 Media.