I tried to track down some of the crazy news stories that were being shared broadly on Facebook and much of what I found was that they were algorithmically generated titles slapped onto the same URL and the actual "story" was copied bits from other semi-related stories.

You'd find really salacious headlines: "Hillary Clinton Murder Victim Speaks" and the actual story would be about her fundraising.

They were arbitraging the cost of buying a FB ad (to drive traffic and start the viral loop) against how many ads they could run on the site.