Check the full post for details; also see Facebook Steps Up (Jeff Jarvis)
"We believe in giving people a voice and that we cannot become arbiters of truth ourselves, so we’re approaching this problem carefully. We’ve focused our efforts on the worst of the worst, on the clear hoaxes spread by spammers for their own gain, and on engaging both our community and third party organizations.News Feed FYI: Addressing Hoaxes and Fake News | Facebook Newsroom
The work falls into the following four areas. These are just some of the first steps we’re taking to improve the experience for people on Facebook. We’ll learn from these tests, and iterate and extend them over time."