Facebook disputed the report, which was
published Thursday, saying that it "vastly overstated what this bug was
because ultimately it had no meaningful, long-term impact on problematic
content," according to Joe Osborne, a spokesman for parent company Meta.
But the bug was serious enough for a group
of Facebook employees to draft an internal report referring to a "massive
ranking failure" of content, The Verge reported.
In October, the employees noticed that some
content which had been marked as questionable by external media - members of
Facebook's third-party fact-checking programme - was nevertheless being favored
by the algorithm to be widely distributed in users' News Feeds.
"Unable to find the root cause, the
engineers watched the surge subside a few weeks later and then flare up
repeatedly until the ranking issue was fixed on March 11," The Verge
reported.
But according to Osborne, the bug affected
"only a very small number of views" of content.
That's because "the overwhelming
majority of posts in Feed are not eligible to be down-ranked in the first
place," Osborne explained, adding that other mechanisms designed to limit
views of "harmful" content remained in place, "including other
demotions, fact-checking labels and violating content removals."
AFP currently works with Facebook's fact
checking programme in more than 80 countries and 24 languages. Under the
programme, which started in December 2016, Facebook pays to use fact checks
from around 80 organisations, including media outlets and specialised fact
checkers, on its platform, WhatsApp and on Instagram.
Content rated "false" is
downgraded in news feeds so fewer people will see it. If someone tries to share
that post, they are presented with an article explaining why it is misleading.
Those who still choose to share the post
receive a notification with a link to the article. No posts are taken down.
Fact checkers are free to choose how and what they wish to investigate.