Multiple accounts used by the same person are harmful and can propagate fake news sjscreens / Alamy Stock Photo

“Sock puppets” are the scourge of online discussion . Multiple accounts controlled by the same user can dominate comment forums and spread fake news. But now there’s a way to unmask the puppeteers.

A study of nine websites that use comment service Disqus to let readers post responses to articles found that sock puppets can be identified based on their writing style, posting activity and relationship with other users.

In the era of fake news, detecting sock puppets is important, says Srijan Kumar at the University of Maryland. “Whenever multiple accounts are used by the same party it is harmful and it skews the discussion and fake news can be propagated very confidently,” he says.


Kumar and his colleagues at the University of Maryland and Stanford University in California analysed commenter accounts on news websites including CNN, NPR, Breitbart and Fox News. They identified the sock puppets by finding accounts that posted from the same IP address in the same discussion at similar times. This approach isn’t always possible, so they wanted to develop a tool that automatically detects sock puppets based only on publicly accessible posting data.

They found that sock puppets contribute poorer quality content, writing shorter posts that are often downvoted or reported by other users. They post on more controversial topics, spend more time replying to other users and are more abusive. Worryingly, their posts are also more likely to be read and they are often central to their communities, generating a lot of activity.

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Based on their findings, the researchers created a machine learning tool that can detect if two accounts belong to the same person 91 per cent of the time. Another tool can distinguish between a regular account and a sock puppet with 68 per cent accuracy. The research will be presented this week at the World Wide Web Conference in Perth, Australia.

This is the most comprehensive investigation of sock puppets in discussion forums, says Meng Jiang, who studies suspicious online behaviour at the University of Illinois at Urbana-Champaign.

But given that the group used sock puppets already identified by their IPs, it’s impossible to know if the tool could detect sock puppets the IP approach missed, he says. A real-world system would likely incorporate both approaches.

Kumar is confident the new tool could detect other sock puppets, and points out that IP addresses are not always available and can easily be spoofed.

The system could be useful to detect sock puppets on any forum that makes an account’s posting history available, such as social media site Reddit and most websites’ comment sections, he says. A person could then verify if an account breaches the site’s rules. “These tools always have a human in the loop,” he says. “It would flag suspicious accounts and a moderator would decide.”