FACTBOX-What is QAnon and how are social media sites taking action on it?

QAnon followers espouse an intertwined series of beliefs, based on anonymous Web postings from Q, who claims to have insider knowledge of the Trump administration.

President Donald Trump is secretly fighting a cabal of child-sex predators that includes prominent Democrats, Hollywood elites and deep state allies.

QAnon, which borrows some elements from the bogus pizzagate theory about a pedophile ring run out of a Washington, D.C., restaurant, has become a big tent conspiracy theory encompassing misinformation about topics ranging from alien landings to vaccine safety.

Media investigations have shown that social media recommendation algorithms can drive people who show an interest in conspiracy theories toward more material.

A report by the Institute for Strategic Dialogue found that the number of users engaging in discussion of QAnon on Twitter and Facebook have surged this year, with membership of QAnon groups on Facebook growing by 120% in March.

Researchers say Russian government-supported organizations are playing a small but increasing role in amplifying the conspiracy theories.

QAnon backers helped organize real-life protests against child trafficking in August and were involved in a pro-police demonstration in Portland, Oregon.

A review of Amazon.com Inc and Ebay Inc showed sellers listing QAnon-branded items including books, face masks, T-shirts and hats.