A major U.S. Supreme Court case on Internet free speech is Reno v. ACLU. In that case, the Supreme Court struck down the CDA. As part of its ruling, the Court granted the highest level of First Amendment protection to speech conducted over the Internet. In Reno, the Court distinguished the Internet which has much weaker First Amendment protections from broadcast media and placed the Internet squarely among traditional media such as books and newspapers. By doing so, the Court helped establish unequivocally that the Internet is entitled to the broadest First Amendment protections.

In 1997, the Supreme Court held unanimously in Reno v. American Civil Liberties Union that the CDA constituted an unconstitutional restriction on speech on the Internet. The court found the Internet to be a “unique and wholly new medium of worldwide human communication” deserving of full First Amendment protection. Lawmakers may only regulate obscenity; consequently, the regulations contained in the CDA would reduce the constitutionally protected material available to adults “to only what is fit for children.” According to the Supreme Court, the unique features of Internet communications such as its availability and ease of use were critical to its decision.