Facebook is being asked by some people to do something about fake news. Does the term "fake news" refer to hit and run operations that try to get traffic for a particular article, or does it also refer to organisations which are heavily biased and have a tenuous relationship with reality, but have a sustained readership?
Fake news on Facebook
There were actual fake (as in not published by news sites and not based on fact) news stories posted on Facebook. They'd use Facebook to drive traffic and make money via advertising.
The interesting part is that the people outside the US were apparently doing it purely for profit. Apparently the ad revenue from fake news articles posted on Facebook was enough to make a decent income in Macedonia.
It's a fascinating intersection of Donald Trump's celebrity, Clinton's unpopularity, and right wing hunger for news. And it doesn't even require actual malfeasance. It's possible that it arose on its own, although it is also possible that someone like Roger Stone (Trump's version of Bob Creamer) started it. Regardless, it seems to have spread into a cottage industry.