A new tool that shows how fake news and unverified stories spread through social media has been developed by researchers at a US university.
The search engine - dubbed Hoaxy - is the latest effort to combat the proliferation of fake news, which proliferated during the US presidential campaign, with one bogus post-Election Day story sparking a real-life event when a gunman fired shots into a Washington DC restaurant.
"It is a very serious problem," said Filippo Menczer, the director of Indiana University's Center for Complex Networks and Systems Research, which launched Hoaxy.
Misinformation and propaganda are not new, but Mr Menczer said social media had added a new component, because the information was pre-selected to be in line with people's own opinions.
"Social media makes it more likely that I am more exposed to false information that I am likely to believe," he added.
Hoaxy did not determine whether a story was real, but it showed how it was spread online and showed related fact-checking.
The free website - hoaxy.iuni.iu.edu can be used by reporters, researchers and the public. If a user suspects a story is false they can search it in the website to see how it was spread and to what degree it went viral.
"There is no editorial judgment," Mr Menczer said. "We don't look at the claims, or vet them, or say they are true or false."
It examined websites, compiled by news organizations and fact-checking sites, that were known to post satire, hoaxes or conspiracy theories. It also tracked links to the stories on Twitter and Facebook so users could see how often the stories had been shared.
"You can observe who are the hubs, who are the main spreaders and most influential who have spread these claims and fact-checks," said Mr Menczer.
News and tech companies, including Facebook and Twitter, are also trying to tackle fake news and have formed a coalition to improve the quality of information on social media.
Mr Menczer said he started looking into the phenomenon of false news in a research experiment several years ago.
He created a website with celebrity stories clearly marked as fake and promoted them on social bookmarking websites that were popular at the time. A month after launching the site he received a check for ad revenue from the site.
"That early experiment demonstrated the power of the internet to monetize false information," he said.