China's We Chat "shadow-bans" messages with forbidden keywords, but only for China-based accounts

The University of Toronto's Citizen Lab (previously) continues its excellent work, this time with a deep investigative piece on a sneaky form of censorship in China's popular We Chat service, where messages posted to group chats that contain words on a government blacklist are made invisible to other participants in the chat, while the original poster still sees it, giving the illusion that everyone's read the controverial message but no one found it worth commenting upon.



This practice is similar to "shadow banning," which has been tried on many western platforms, from Metafilter to Reddit -- that's when all of a user's posts are blocked for everyone except the banned user, so it seems that every sees the inflammatory posts, but no one rises to the bait.

It's the latest wrinkle in We Chat's longrunning project to censor subjects deemed controversial by the country's internet censors. In previous versions, all We Chat posts containing banned words were blocked and the user making the post was warned about it. The current version only targets accounts originally registered to phones with Chinese phone numbers.

On the other hand, merely censoring the internet is relatively lenient: in France, a man was just sentenced to two years in prison, just for looking at ISIS-affiliated websites.


Keyword filtering on WeChat is only enabled for users with accounts registered to mainland China phone numbers, and persists even if these users later link the account to an International number.

Keyword censorship is no longer transparent. In the past, users received notification when their message was blocked; now censorship of chat messages happens without any user notice.

More keywords are blocked on group chat, where messages can reach a larger audience, than one-to-one chat.

Keyword censorship is dynamic. Some keywords that triggered censorship in our original tests were later found to be permissible in later tests. Some newfound censored keywords appear to have been added in response to current news events.

WeChat’s internal browser blocks China-based accounts from accessing a range of websites including gambling, Falun Gong, and media that report critically on China. Websites that are blocked for China accounts were fully accessible for International accounts, but there is intermittent blocking of gambling and pornography websites on International accounts.

One App, Two Systems: How WeChat uses one censorship policy in China and another internationally

[Lotus Ruan, Jeffrey Knockel, Jason Q. Ng, and Masashi Crete-Nishihata/Citizen Lab]

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