“#1: 47 USC 230
This law was enacted in 1996 (as part of the Communications Decency Act, discussed below) during the heyday of the cyberspace exceptionalism movement—about the same time as Barlow’s Declaration of Independence and Johnson/Post’s Internet self-governance article. Indeed, this law is one of the most conspicuous examples of how a legislative body has set different rules for physical space and cyberspace. In this case, the law provides websites and other intermediaries a near-absolute immunization from liability for their users’ content—even if offline publishers would be liable for publishing the exact same user content in dead trees.
It’s hard to overstate the importance of this law to the Internet’s evolution. Without this law, all Internet content probably would be subject to a notice-and-takedown regime like we have for copyright law (see discussion about the DMCA Online Safe Harbors below). If websites had to remove user content upon notice to avoid liability, they would act conservatively, quickly pulling down complained-about content without much fuss. So, any company unhappy with negative consumer comments could simply contact the web host, claim that the comments were defamatory (making the web host potentially liable for the content), and expect the web host to scramble to take down the user’s comment.
But in this takedown melee, only negative remarks would be targeted (there would be no legal grounds—or reason—to target positive comments). Thus, notice-and-takedown rules would result in “lopsided” databases in which only positive opinions/commentary would remain, but many negative comments could be quickly excised. This would ruin the capability of the consumer opinion sites (for example, eBay’s feedback forum and Amazon product reviews) to hold people and companies accountable for their choices. Indeed, by undermining the credibility of Internet content generally, a notice-and-takedown scheme could diminish the Internet’s vitality as a mainstream information resource.
47 USC 230 eliminates the notice-and-takedown option for people and companies trying to escape accountability. As a result, 47 USC 230 is a big part of the reason why the Internet became such a massive success.”
From, “The Best and Worst Internet Laws,” Eric Goldman, Informit.com