https://phys.org/news/2018-06-facebook-trending-topics-news.html

When Facebook launched "trending" in 2014 as a list of headlines to the side of the main news feed, it was a straightforward move to steal users from Twitter by giving them a quick look at the most popular news of the moment. It fit nicely into CEO Mark Zuckerberg's pledge just a year earlier to make Facebook its users' "personal newspaper."

But that was then. "Fake news" wasn't yet a popular term, and no foreign country had been accused of trying to influence the U.S. elections through social media. Trending news that year included the death of Robin Williams, Ebola and the World Cup.