The Electronic Frontier Foundation writes: Section 230 of the Communications Decency Act
47 U.S.C. § 230, a Provision of the Communication Decency Act
Tucked inside the Communications Decency Act (CDA) of 1996 is one of the most valuable tools for protecting freedom of expression and innovation on the Internet: Section 230.
This comes somewhat as a surprise, since the original purpose of the legislation was to restrict free speech on the Internet. The Internet community as a whole objected strongly to the Communications Decency Act, and with EFF's help, the anti-free speech provisions were struck down by the Supreme Court. But thankfully, CDA 230 remains and in the years since has far outshone the rest of the law. "Section 230 says that "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" (47 U.S.C. § 230).
In other words, online intermediaries that host or republish speech are protected against a range of laws that might otherwise be used to hold them legally responsible for what others say and do. The protected intermediaries include not only regular Internet Service Providers (ISPs), but also a range of "interactive computer service providers," including basically any online service that publishes third-party content.
Though there are important exceptions for certain criminal and intellectual property-based claims, CDA 230 creates a broad protection that has allowed innovation and free speech online to flourish."
I wish the Bill of Rights had started with the first stating "Congress shall make no Law" and left it at that.