Niall Ferguson is the Laurence A. Tisch professor of history at Harvard University. His new book, The Square and the Tower, will be published by Penguin on Oct. 5.
Shortly after last year's U.S. presidential election, Mark Zuckerberg, co-founder and chief executive of Facebook, dismissed the notion that fake news might have decided the contest in Donald Trump's favour as "a pretty crazy idea." Last week, he had to admit that he regrets those words.
We now know that before (and after) the election, Russian trolls with bogus identities bought about 3,000 Facebook advertisements. Even though only $100,000 (U.S.) was spent, the ads could have been seen by tens of millions of people. Moreover, the Russians also used Facebook Events (the company's event-management tool) to organize phoney political protests in America, including an Aug. 27 anti-immigrant rally in a small Idaho town known for welcoming refugees. The event was to be "hosted" by "SecuredBorders," a Facebook group exposed in March as a Russian front.
Twitter was used in a similar way, it turns out. In response to continuing congressional investigations, the company admitted last week that it had identified about 200 accounts linked to Russia, and that the Kremlin-backed news site RT had spent a quarter of a million dollars on Twitter ads last year.
Related: Facebook to hire 1,000 people to review ads after Russian interference
It is still too early to conclude that Russian use of social media decided the election. However, we probably can conclude that social media decided it. It seems that the Russians were aiming more to widen political divisions in the United States than to get Mr. Trump elected. The Trump campaign was aiming to get its man elected – and it spent far more than $100,000 on Facebook. According to the campaign's digital director, Brad Parscale, about $90-million went on social media, most of it on Facebook. "Facebook and Twitter were the reason we won this thing," said Parscale last November. I believe he is right.
The only indicators that reliably predicted the election result were Facebook and Twitter. Mr. Trump dominated Hillary Clinton on both. If the social media platforms had not existed, Mr. Trump would have been forced to conduct a more conventional campaign, in which case the greater financial resources of his opponent – who outspent him by more than two to one – would surely have been decisive.
In less than a decade, the public sphere – and the democratic process – have been revolutionized. In 2008, defeated Republican presidential candidate John McCain had just 4,492 Twitter followers and 625,000 Facebook friends. Barack Obama had four times as many Facebook friends as Mr. McCain and 26 times as many Twitter followers. Yet the platforms were still in their infancy then. Facebook had only been created at Harvard four years earlier. Twitter was set up in March 2006.
Today, by contrast, Facebook has more than two-billion users around the world. In the United States, two-thirds of American adults are on Facebook. Nearly half – 45 per cent – get their news from Facebook. One in 10 gets news from Twitter. About 40-million people (and bots) follow @realDonaldTrump.
Much of what gets said on Facebook is inane. The eighth most-popular word used by American Facebook users on their status updates – after "day," "loud," "word," "ticket," "nice," "long," and "light" – is "hangover." And most of what gets said on Facebook is probably true; after all, why lie about your hangover?
The problem is not just the outright fake news, such as that non-existent anti-immigrant rally in Idaho – though that problem will persist as long as identities can be made up without verification. The real problem is the fact that everyone – not only Russian trolls – can use social networks not just to spread falsehoods but to spread extreme opinions. This is a key problem with all social networks that the titans of Silicon Valley gravely underestimated. Because of the phenomenon known as homophily – the tendency for "birds of a feather to flock together" – like-minded people form clusters in more or less any social network, regardless of its size.
In giant online networks, the result is massive, self-reinforcing polarization. One recent study of 665 blogs and 16,852 links between them showed that they formed two almost separate clusters: one liberal, the other conservative. A similar study of Twitter revealed that retweets have the same dichotomous character: Conservatives retweet only conservative tweets. Most striking of all, a newly published study of language used on Twitter demonstrates that on hot-button issues such as gun control, same-sex marriage and climate change, it's the tweets that use moral and emotional language that are more likely to be retweeted.
The sky is darkening over Silicon Valley. Facebook or Fakebook? Twitter or Twister? Last week, Mr. Trump fired his first (and characteristically ungrateful) shot directly at Facebook: "Facebook was always anti-Trump." Mr. Zuckerberg shot back: "That's what running a platform for all ideas looks like."
The key question is how tenable that defence is now. A platform for all ideas? Or the most powerful publisher in the history of the world? We used to think William Randolph Hearst – the inspiration for Citizen Kane – deserved that title. But Citizen Zuck has surely outstripped him.
In China, he is excluded. In Europe, he is increasingly regulated. But in America? Watch this Face.
©Niall Ferguson/The Sunday Times, London