This story was originally published at 6:35 p.m. EDT. It has been updated to add Mark Zuckerberg’s comments.
Facebook’s Trending news section includes topics that aren’t actually trending on Facebook, according to a statement from the company today.
The admission came after The Guardian published a trove of documents, including a copy of Facebook’s “Trending Review Guidelines” used to train workers—known internally as “news curators”—who run the platform’s trending section. As Gizmodo previously reported, Facebook’s trending section is run largely like a newsroom and curators can “inject” and “blacklist” topics.
Facebook’s vice president of global operations Justin Osofsky today said topics that can be included in the trending module are first surfaced by an algorithm that “identifies topics that have recently spiked in popularity on Facebook.”
But that algorithm “also uses an external RSS website crawler to identify breaking events,” Osofsky’s statement continued.
Osofsky’s statement appeared to contradict a statement released by Facebook’s vice president of search Tom Stocky on Tuesday in response to Gizmodo’s reporting. In that statement, Stocky said the trending module was “designed to showcase the current conversation happening on Facebook.” Stocky also said that “we do not insert stories artificially into trending topics.” Stocky’s statement does not acknowledge the use of an RSS feed to pipe in topics not generating organic buzz on Facebook.
The trending review guidelines released today refer to both “organic” and “external” topics that are surfaced via algorithm for inclusion in the trending module. Organic topics indicate a subject being “mentioned on Facebook significantly more than its normal level of buzz,” while external topics “are detected by crawling RSS feeds of headlines from top news sites.”
“They used external topics all the way until I stopped working there,” said one former curator, who left Facebook in mid-2015 and describes Stocky’s statement from earlier this week as “bullshit.”
“The idea behind external topics was to push more hard news into people’s feeds,” the same individual said. “It was a form of injection into the back-end algorithm list of trending topics.”
Until recently, the workings of Facebook’s trending module have been largely opaque. In a 2015 story by Recode, the trending module is portrayed as one governed almost entirely by algorithm. The company’s own website still describes the module in the following way:
Trending shows you topics that have recently become popular on Facebook. The topics you see are based on a number of factors including engagement, timeliness, Pages you’ve liked and your location.
Facebook also released a list of 1,000 publications which comprised the RSS feeds as of today.
Osofsky said the company “will continue to investigate the allegations” by a Gizmodo source who said that conservative news was routinely prevented from reaching the trending section.
“We have found no evidence to date that Trending Topics was successfully manipulated, but will continue the review of all our practices,” he said.
[Disclosure: Facebook has launched a program that pays publishers, including the New York Times and Buzzfeed, to produce videos for its Facebook Live tool. Gawker Media, Gizmodo’s parent company, recently joined that program.]
Update 9:21 p.m. : Mark Zuckerberg addressed the controversy tonight:
I want to share some thoughts on the discussion about Trending Topics.
Facebook stands for giving everyone a voice. We believe the world is better when people from different backgrounds and with different ideas all have the power to share their thoughts and experiences. That’s what makes social media unique. We are one global community where anyone can share anything — from a loving photo of a mother and her baby to intellectual analysis of political events.
To serve our diverse community, we are committed to building a platform for all ideas. Trending Topics is designed to surface the most newsworthy and popular conversations on Facebook. We have rigorous guidelines that do not permit the prioritization of one viewpoint over another or the suppression of political perspectives.
This week, there was a report suggesting that Facebook contractors working on Trending Topics suppressed stories with conservative viewpoints. We take this report very seriously and are conducting a full investigation to ensure our teams upheld the integrity of this product.
We have found no evidence that this report is true. If we find anything against our principles, you have my commitment that we will take additional steps to address it.
In the coming weeks, I’ll also be inviting leading conservatives and people from across the political spectrum to talk with me about this and share their points of view. I want to have a direct conversation about what Facebook stands for and how we can be sure our platform stays as open as possible.
The reason I care so much about this is that it gets to the core of everything Facebook is and everything I want it to be. Every tool we build is designed to give more people a voice and bring our global community together. For as long as I’m leading this company this will always be our mission.