The social networking site Facebook has confirmed its scoring some of its members on a trustworthiness scale in an attempt to combat "fake news."
The Washington Post revealed the social networking site had developed the system over the past year.
The tech firm said it developed the system to help handle reports of false news on its platform, but it declined to reveal how the score was calculated or the limits of its use.
Critics are concerned that users have no apparent way to obtain their rating.
The BBC understands that at present only Facebook's misinformation team makes use of the measurement.
The tech firm has, however, objected to the tool being described as a reputation rating.
"The idea that we have a centralised 'reputation' score for people that use Facebook is just plain wrong and the headline in the Washington Post is misleading," said a spokeswoman.
"What we're actually doing: We developed a process to protect against people indiscriminately flagging news as fake and attempting to game the system."
"The reason we do this is to make sure that our fight against misinformation is as effective as possible," she said.
The Washington Post's report was based on an interview with Facebook executive Tessa Lyons about the platform's battle against "fake news".
It reported that she said it had been developed to improve a fact-checking scheme begun in 2016, in which posts that Facebook users flag as being false are sent to third-party organisations to decide if they should appear lower in people's news feeds.
To make the system more efficient, she explained, her team wanted to know which flaggers were themselves trustworthy.
"People often report things that they just disagree with," Ms Lyons explained, adding that the system gave users a score between zero and one.
The BBC understands that this is calculated in part by correlating the false news reports with the ultimate decisions of the independent fact-checkers.
So, someone who makes a single complaint that is substantiated gets a higher score than someone who makes lots of complaints, only some of which are determined to be warranted.
But The Washington Post said Ms Lyons had declined to say what other signals were being used to avoid tipping off bad actors about how to game the system.
'Automated and opaque'
Facebook is far from being the first tech firm to privately score its users.
Uber has long rated its customers according to the marks each driver gives them. In 2010 Twiiter's co-founder Ev Williams said it gave users a secret "reputation score" to help it recommend which members to follow.