The researchers gathered the names of hundreds of thousands of public Facebook and Twitter accounts over 18 months and, using criteria defining junk news, winnowed them to a list of "obvious" sites, Howard said. "These are the sites that anybody in their right mind would qualify as extremist, sensationalist, conspiratorial."
"They use swear words in the headlines –– or all capital letters. It's stuff you might call commentary masking as news, if you were being generous."
Among those on the study's list are Breitbart News and InfoWars, two popular far-right sites that have been especially sympathetic to Trump and his administration.
McClatchy reported in March that federal investigators were examining whether those or other ultra-right sites collaborated in any way with Russia's cyber operation aimed at disrupting the 2016 U.S. presidential election and ultimately, according to top U.S. intelligence agencies, sought to defeat Hillary Clinton and elect Trump.
Under pressure from investigators for the House and Senate intelligence committees, Facebook and Twitter since have conducted internal investigations and found that Russian operatives created tens of thousands of automated election-related accounts on Twitter and hundreds of fake accounts on Facebook.
There has been no indication that either Breitbart or InfoWars has been implicated in investigations by special counsel Robert Mueller and the intelligence committees, which also are investigating whether Trump's campaign colluded with Russian operatives.
In addition, the researchers' list of "junk" sites includes the conservative-leaning National Review; Hannity.com, the site of Fox News talk show host Sean Hannity, who has steadfastly backed Trump and calls Mueller's investigation "a house of cards that's now crashing down," and the New York Daily News.
Among a sample of Twitter users with strong connections to one of 10 groups along the political spectrum, the researchers found that 96 percent of Trump backers widely shared "junk" news and did so more than all other groups combined; the groups included military and gun rights supporters, liberals and other Democrats. Among 13 similar categories of Facebook users, 91 percent of "hard conservatives" circulated junk news, also more than all other categories combined.
On the positive side, the researchers found that most Americans, including members of both the Democratic and Republican parties, were not targeted with junk news and tended not to share it.
The White House did not respond to a request for comment on the study.
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