TikTok has blocked a series of hashtags related to QAnon's conspiracy theory from appearing in search results, amid concerns about misinformation, the BBC has learned.
Days go by after Twitter has banned thousands of accounts related to QAnon.
QAnon is a far-reaching and unfounded conspiracy theory, whose followers support U.S. President Donald Trump.
They believe that the president is fighting against a clandestine "deep state" network of political, economic and media elites.
TikTok said it moved to limit "QAnonTruth" searches after a question from the BBC's anti-disinformation unit, which noted a spike in conspiracy videos using the tag. The company expressed concern that such misinformation could harm users and the general public.
"QAnon" and related hashtags, such as "Out of Shadows", "Fall Cabal" and "QAnonTruth", will no longer return search results on TikTok, although videos that use the same tags will remain on the platform.
Videos that use the "QAnon" hashtag, in particular, have millions of cumulative views and can still be found if a user's algorithm directs them to the associated content.
Many videos promote unfounded conspiracy theories. Some of them recently supported unfounded claims linking Wayfair furniture firm to child trafficking.
TikTok's intervention comes after Twitter announced measures earlier this week to also crack down on QAnon's conspiracy theorists, including banning thousands of accounts.
He said the suspensions will be applied to accounts that "are involved in violations of our multi-account policy, coordinating abuses against individual victims or attempting to circumvent a previous suspension."
Twitter also said it would stop recommending content linked to QAnon and prevent the URLs associated with it from being shared on the platform in an attempt to prevent "offline damage".
Celebrities, including the Chrissy Teigen model, have been the victim of coordinated abuse by QAnon conspiracy theorists in the past few weeks.
Sources close to Facebook say that the social media site is trying to act similarly on supporters of conspiracy theory. The QAnon groups on the site have hundreds of thousands of members cumulatively.
What is QAnon?
QAnot started in October 2017 on the 4chan anonymous wall. One user claimed to have the highest level of security within the United States government and signed their posts as "Q", hence the name QAnon. Q communicates in cryptic places and claims to be directly involved in a secret investigation into a global network of pedophiles.
The total list of QAnon's claims is enormous - and often contradictory.
More recently, QAnon conspiracy theorists have released a number of unfounded coronavirus conspiracy theories, ranging from claims about the "hoax" pandemic to quirky hints about masks and vaccines.
The central theory about an evil "deep state" elite network, followed by the 2016 "pizzagata" saga - a false theory about Democratic Party politicians running a pedophile ring outside a Washington pizza restaurant.
Many QAnon influencers have a large audience on social media. They urge followers to "do their own research" - in other words, watch YouTube videos and talk to other supporters - to solve Q puzzles.
