© Screenshot from Facebook
"We are running a small test which shows the text '[Satire]' in front of links to satirical articles in the related articles unit in News Feed," a Facebook spokesperson told ArsTechnica.
"This is because we received feedback that people wanted a clearer way to distinguish satirical articles from others in these units."
The new tag will highlight stories after a user has clicked through to a link in their news feed. The related content which appears after a link is clicked will be marked out with the [satire] tag.
Other satirical sites have been marked out with similar tags. While a full list of satirical sites to be marked out has not yet been provided, The New Yorker's Borowitz Report has frequently been mistaken as a real news source in the past, as has Buzzfeed parody Clickhole and UK site the Daily Mash.
The move comes after repeated cases of people mistaking the articles for real news stories.
In July, Science News accidentally ran a story about schadenfreude in children that included Onion content, prompting them to change the story: "This article was amended on July 24, 2014, to delete a sentence that unintentionally linked to a parody article. Science News regrets the error but does think the parody article is pretty funny."
A further piece about a 9,600-mile-long rollercoaster or "endurance coaster" was also taken at face value by commenters on a website called "Literally Unbelievable" which documents bizarre face-value responses to Onion content.
In November 2012, China's People's Daily also made headlines when North Korean leader Kim Jong-un was declared the Sexiest Man Alive for 2012 by The Onion, prompting the Chinese Communist Party's official newspaper to reprint quotes about his "devastatingly handsome, round face, his boyish charm," and only later removing the article from its website.
For the CIA-NSA's Facebook to 'mark' other articles that don't conform to Establishment standards.