In a blog post, Facebook noted that users considered stories "authentic" when they were "genuine and not misleading, sensational or spammy." The tweaks to individuals' News Feeds will reflect that preference -- not just by burying fake news, but also by lowering the visibility of clickbait stories and Pages that urge folks to like, share and subscribe. To train their system to cull non-authentic posts, Facebook identified Pages that begged for engagement and/or that users had manually hidden, then fed that activity into a computer model to detect similarly low-quality content as it's posted.
The new tweaks will also boost viral stories. Individual Pages posts or topics across Facebook getting lots of engagement will be pushed higher in users' personal News Feeds, at least temporarily. Both adjustments are more about presenting more relevant and resonant content than expressly combating fake news, but refining the News Feed's algorithms will hopefully improve the quality of posts churning in front of users' eyes.