Law prof Benjamin Zipursky has written The Monsanto Lecture: Online Defamation, Legal Concepts, and the Good Samaritan. Here's the abstract:
Federal and state courts around the country – aided by academics on almost all sides – have completely misread the Communications Decency Act [“CDA”] § 230(c). This widely cited provision was designed to protect Internet service providers and certain Internet users from liability for the defamatory statements posted by others online. Congress did not want these actors to face a defamation-law equivalent of a duty to rescue strangers -- an affirmative duty to remove third parties’ defamatory statements about others. And it certainly did not want a service provider’s efforts to protect a stranger’s reputation to backfire by suddenly creating liability for everything the service provider failed to remove. So, like every state legislature has done for off-duty medical personnel who act as good Samaritans, Congress in 1996 created a law saying that good faith efforts to filter offensive or defamatory material do not create an affirmative duty to remove such material and do not open them up to liability. For good measure, the statute also laid down a basic rule that there is no liability simply for being the conduit of what others have posted or for failing to remove such postings from one’s own site, and it preempts any state law that does otherwise. The CDA thus ensures that states’ defamation law runs roughly parallel to duty-to-rescue doctrine in the common law of negligence as amended by good Samaritan statutes. Indeed, that is why “Good Samaritan” is in the title of CDA § 230(c).
Under the sway of a talented First Amendment bar and in an academic culture hostile to common law concepts, judges around the country have selected an entirely different and misguided interpretation of § 230(c). They read the statute as, in effect, an abrogation of libel law’s classic republication rule, which states that a person who republishes a defamatory statement is liable as if she were the one who first said it. According to the overwhelmingly dominant interpretation of courts today, once someone says something defamatory, anyone who reposts it enjoys complete immunity from all state and federal law, even if the republisher knows the statement to be false and defamatory. Those academics who have rejected this interpretation tend to swing to the other extreme, advocating that website owners who have notice of a defamatory posting should be liable for failure to remove it. This too misses the point of the statute’s text. Through a detailed examination of libel doctrine and a close analysis of the case (Stratton Oakmont v. Prodigy) that generated the development of a protective federal statute, the article displays the correct reading of the statute and the importance of retaining a robust version of the republication rule online.