The moment Joe Biden was sworn in as president of the United States, a collective outcry by Trump supporters rippled across social media: 

"Where are the mass arrests?" "Where is the storm?" "Military special ops failed us!" and the ever-popular, "I am in tears!" 

The mass wailing from members of QAnon, an online conspiracy that believes former President Trump will return in an apocalyptic event to arrest and jail Satan-worshiping Democrats, epitomizes the unique challenge facing Mr. Biden as he tries to implement an ambitious social and economic agenda. In an age where nearly all information is channeled through the vagaries of social media, disinformation is rampant and given more credence with every share. And that means regulating online content, along with ending the pandemic and healing the economy, should be at the top of Mr. Biden's agenda.