If you are hosting comments in the USA, you need to learn about the main law that covers liability and immunity around the content of user-submitted comments, section 230 of the Communications Decency Act (1996), aka CDA 230.
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Section 230 of the Communications Decency Act (CDA 230) will likely shield you from certain kinds of liability for problematic statements made by your users, guests, and other third parties on your site, even if you moderate this content. Keep in mind that CDA 230 only protects from content created by a third party. It does not shield you from liability for your own statements or for potential copyright and trademark violations.
No provider or user of an interactive computer service shall be treated as the publisher or speaker of any information provided by another information content provider.