The Supreme Court will be answering this question before long in Twitter, Inc. v. Taamneh and Gonzalez v. Google LLC –

Background summary by the guys at Not the Bee:
Three decades ago, lawmakers protected internet companies by passing Section 230, a provision that exempts them from liability if someone says or does something illegal on their site. The argument is that a website like Facebook is not a publisher that condones or controls what is being written on the site; therefore, it should not be liable for lawsuits. But as we've seen from exposés like The Twitter Files, these websites ARE acting like publishers by choosing what content is allowed based on their ideological preferences. If Facebook bans sites like ours for posting stories that refer to men in wigs as men, then the argument goes that they should be liable to all the legal bindings of a formal publisher. If Section 230 is repealed, it would drastically change free speech on the internet... but not in all good ways...