If you have web forums, allow reader comments, host guest bloggers on your site, or if you repost information that you receive from RSS feeds, you generally will be shielded from liability for defamatory statements made by your users and guests under section 230 of the Communications Decency Act ("Section 230"). This important federal law protects you from certain types of liability, including defamation, associated with the statements and other user-submitted content you publish on your site.
Section 230 grants interactive online services of all types, including blogs, forums, and listservs, broad immunity from liability so long as the information at issue is provided by a third-party. You will not lose this immunity even if you edit the content, whether for accuracy or civility, and you will be entitled to immunity so long as your edits do not substantially alter the meaning of the original statements. However, if you alter someone else's statement so that it becomes defamatory (e.g., changing the statement “Bob is not a murderer” to “Bob is a murderer”), you would be responsible for the content of the edited statement; and if it turns out to be untrue, you could be liable for defamation. In addition, if you add your own commentary along with the user-submitted content, you will only be shielded from liability for the material created by your user, not for your own statements. For more on this important protection, see the section on Immunity for Online Publishers Under the Communications Decency Act.
Note that Section 230 does not shield you from liability for copyright infringement claims and other intellectual property claims. If you publish or use the creative work of others, their trademarks, or certain confidential business information without the permission of the owner, you may be exposing yourself to legal liability for violations of intellectual property law. Fortunately, if you allow your site's user to post this type of content you can protect yourself from copyright infringement claims under the Digital Millennium Copyright Act (DMCA), so long as you establish effective "notice-and-takedown" procedures, promptly remove content when a copyright owner notifies you that it is infringing, and have no knowledge that the material in question is infringing. We cover liability associated with copyright, trademark, and trade secrets in the Intellectual Property section of this legal guide. For guidance on the procedures you should follow under the DMCA, see the section on Protecting Yourself Against Copyright Claims Based on User Content.