"Section 230" exemptions of the Communications Decency Act state 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." This clause effectively provides a general immunity for websites that host user-generated content that is defamatory, deceptive or otherwise harmful, even if the operator knows that the third-party content is harmful and refuses to take it down. An exception to this general rule may exist if a website promises to take down the content and then fails to do so. Copyright laws Copyright laws also play a factor in relation to user-generated content, as users may use such services to upload works—particularly videos—that they do not have the sufficient rights to distribute. In many cases, the use of these materials may be covered by local "fair use" laws, especially if the use of the material submitted is transformative. Local laws also vary on who is liable for any resulting copyright infringements caused by user-generated content; in the United States, the Online Copyright Infringement Liability Limitation Act (OCILLA)—a portion of the Digital Millennium Copyright Act (DMCA), dictates safe harbor provisions for "online service providers" as defined under the act, which grants immunity from secondary liability for the copyright-infringing actions of their users, as long as they promptly remove access to allegedly infringing materials upon the receipt of a notice from a copyright holder or registered agent, and they do not have actual knowledge that their service is being used for infringing activities. In the UK, the Defamation Act of 1996 says that if a person is not the author, editor or publisher and did not know about the situation, they are not convicted. Furthermore, ISPs are not considered authors, editors, or publishers and they cannot have responsibility for people they have no "effective control" over. Just like the DMCA, once the ISP learns about the content, they must delete it immediately. The European Union's approach is horizontal by nature, which means that civil and criminal liability issues are addressed under the Electronic Commerce Directive. Section 4 deals with liability of the ISP while conducting "mere conduit" services, caching and web hosting services. Research A study on YouTube analyzing one of the Video On Demand systems was conducted in 2007. The length of the video had decreased by two-fold from the non-UGC content but they saw