Social media sites on the Internet have become an increasingly important source of news for many people. For example, a survey found that “44% of Americans get their news from Facebook”. This pattern is a cause for concern, because it is largely unattributable and therefore unaccountable; The Economist asked, in an article entitled Scandal, outrage and politics, “Do social media threaten democracy?”; it argued that they are “spreading untruth and outrage, corroding voters’ judgment and aggravating partisanship”.
Commercial media organisations are at least partly accountable and they want to retain their credibility – although there are exceptions (18.104.22.168). People can publish outright lies or ‘fake news’ on social media, however, without being sued; people pass stories on to others so that the story rapidly gains momentum: ‘going viral’. A Guardian article, How technology disrupted the truth, explained in some detail how this led to “post-truth politics” in the British vote for Brexit. As argued in a New York Times article entitled Am I imagining This?, ‘fake news’ also undermines American politics.
Although falsehoods have always been used in politics, ‘fake news’ is a new term; a BBC article, The (almost) complete history of ‘fake news’, credited Buzzfeed with coining the term after investigating stories coming from a “town in Macedonia called Veles” in 2016 – where people were making money from them. The term ‘click bait’ is used to describe messages which are so incendiary that people eagerly pass them to all their contacts. Since Facebook carries advertising, which pays more on sites which receive a lot of clicks, there is a financial incentive to create fake news.
The algorithms used by social media companies tend to offer information to users based upon their past preferences – creating an ‘echo chamber’ effect where people only hear news that matches their existing attitudes. As described in an Economist article entitled Less Euromaidan, more Gamergate, “These effects are part of what is increasing America’s political polarisation”. And this problem is not confined to America: as the New York Times reported, Europe Combats a New Foe of Political Stability: Fake News.
A phenomenon known as “confirmation bias” ensures that the human brain uncritically absorbs information that matches its existing views whilst tending to disbelieve or ignore information to the contrary. People’s viewpoints get reinforced, as more news of the same sort is fed to them, so they cannot believe that they have been misled.
Politicians now use social media. For example, Donald Trump uses Twitter extensively and, during the American presidential election in 2016, “routinely repeated false news stories and whipped up conspiracy theories … while urging his followers not to trust corrupt traditional media” – as reported in a Guardian article entitled Facebook’s failure: did fake news and polarized politics get Trump elected?.
 A Pew Research survey, entitled News Use Across Social Media Platforms 2016, was published in May 2016 and was available in June 2018 at http://assets.pewresearch.org/wp-content/uploads/sites/13/2016/05/PJ_2016.05.26_social-media-and-news_FINAL-1.pdf. It found that “A majority of U.S. adults – 62% – get news on social media, and 18% do so often”, and that the “two-thirds of Facebook users who get news there, then, amount to 44% of the general population”.
 Salon published an article on 5 February 2017, entitled This is your brain on fake news: what’s behind the human willingness to swallow “alternative facts”, in which Noah Charney explains the phenomenon of confirmation bias and gives examples related to the 2016 American presidential election. The article was available in June 2018 at http://www.salon.com/2017/02/05/this-is-your-brain-on-fake-news-whats-behind-the-human-willingness-to-swallow-alternative-facts/.