After the election, many people blamed Facebook for spreading partisan — and largely pro-Trump — “fake news,” like Pope Francis’s endorsement of Trump, or Hillary Clinton’s secret life-threatening illness. The company was assailed for prioritizing user “engagement,” meaning that its algorithms probably favored juicy fake news over other kinds of stories. Those algorithms had taken ...

Every day, millions of online diarists, or “bloggers,” share their opinions with a global audience. Drawing upon the content of the international media and the World Wide Web, they weave together an elaborate network with agenda-setting power on issues ranging from human rights in China to the U.S. occupation of Iraq. What began as a ...