Facebook said Tuesday it will ban any pages, groups, and Instagram accounts representing the conspiracy theory QAnon from its platform. The move comes three years after the far-right conspiracy theory began. During those years QAnon adherents have embraced a number of different and often contradictory theories, but the basic false beliefs underlying QAnon are claims about a cabal of politicians and A-list celebrities engaging in child sex abuse, and a “deep state” effort to undermine President Trump. Last year an FBI office warned that Q adherents are a domestic terrorism threat. Facebook’s move will be welcomed by some, but the platform has allowed the conspiracy to grow and spread for years. There are now multiple Republicans running for Congress who have expressed support for QAnon. In August, President Donald Trump praised QAnon followers for supporting him. “I don’t know much about the movement other than I understand they like me very much, which I appreciate,” Trump said in the White House briefing room. Facebook has made multiple commitments to banning certain groups and content in the past, but its enforcement of those bans has sometimes been slow and inconsistent — for instance it has sometimes missed prominent accounts or hashtags it should have banned. In August, Facebook cracked down on thousands of accounts across Facebook and Instagram promoting the QAnon conspiracy theory, as well as a range of militia and anarchist groups, amid what the company said was a rise in behavior among those accounts and groups celebrating violence.