In January 2015, Facebook got more aggressive. It wrote a News Feed FYI blog post with the title “Showing Fewer Hoaxes.” People were complaining about fake news and hoaxes, the blog post said, so Facebook would diminish these posts’ reach. “A post with a link to an article that many people have reported as a hoax or chosen to delete will get reduced distribution in News Feed,” the post said. And with that, Facebook began a public fight against fake news.
But the filter bubble was still getting bigger than ever, and it was about to get worse due to a change in the way people were behaving on the site. (Source)