https://www.nytimes.com/2020/10/28/technology/facebook-google-and-twitter-ceos-return-to-washington-to-defend-their-content-moderation.html >For more than two decades, internet companies have been shielded from liability for much of what their users post by a once-obscure rule called Section 230 of the Communications Decency Act. Now that shield — and how internet companies moderate content on their sites — is being questioned by lawmakers on both sides of the political aisle.