Tom Edsall in the NYT:

A decade ago, the consensus was that the digital revolution would give effective voice to millions of previously unheard citizens. Now, in the aftermath of the Trump presidency, the consensus has shifted to anxiety that online behemoths like Twitter, Google, YouTube, Instagram and Facebook have created a crisis of knowledge — confounding what is true and what is untrue — eroding the foundations of democracy.

These worries have intensified in response to the violence of Jan. 6, and the widespread acceptance among Republican voters of the conspicuously false claim that Democrats stole the election.

Nathaniel Persily, a law professor at Stanford, summarized the dilemma in his 2019 report, “The internet’s Challenge to Democracy: Framing the Problem and Assessing Reforms,” pointing out that in a matter of just a few years

the widely shared utopian vision of the internet’s impact on governance has turned decidedly pessimistic. The original promise of digital technologies was unapologetically democratic: empowering the voiceless, breaking down borders to build cross-national communities, and eliminating elite referees who restricted political discourse.

Since then, Persily continued:

That promise has been replaced by concern that the most democratic features of the internet are, in fact, endangering democracy itself. Democracies pay a price for internet freedom, under this view, in the form of disinformation, hate speech, incitement, and foreign interference in elections.

Writing separately in an email, Persily argued that

Twitter and Facebook allowed Trump both to get around legacy intermediaries and to manipulate them by setting their agenda. They also provided environments (such as Facebook groups) that have proven conducive to radicalization and mobilization.