YouTube is an Internet website that specializes in publishing user-posted video clips. As of early 2007 YouTube is one of the top ten most popular websites on the Internet. Started in late 2005, the site was purchased one year later by Google for over one and a half billion dollars. During that time the website amassed a fanbase of over twenty million users, mostly teens and young adults. Two million videos are added to YouTube's stock of 100 million videos every month. While much of the content consists of original amateur home video, many advertisers and media producers are now providing professional content. Media giants CBS, EMI Group, Universal MG, Sony BMG, and Warner MG have all agreed to either provide content to YouTube, or to license their respective copyrighted material for use in independent videos released on the site.
YouTube is built upon standardized, readily-available technologies. Videos can be uploaded in the user's choice of Audio Video Interleave (avi), QuickTime (mov), Moving Picture Experts Group (mpeg), or Windows Media Video (wmv) formats. YouTube's servers automatically convert the video and serve it as Flash Video (flv) format. This provides a mostly hardware- and software- independent solution for YouTube users, as most video recoding devices from cellphones to professional-grade video cameras can record in one of the accepted formats, and the Adobe Flash browser plugin allows videos to be played in any major web browser on all major computer operating systems. Additionally, YouTube encourages the syndication of its videos on users' webpages and blogs by providing the HTML code necessary for such integration. While YouTube does not actively prevent users from downloading video clips to their computers, it does discourage the practice.
Like most other social-networking sites, YouTube has been the focus of much controversy. Issues regarding sensitive political and personal topics have seen the site banned in several countries including Brazil, Turkey, and India. Popular, controversial videos such as the Saddam Hussein hanging and Naruto anime have seen the topic of YouTube blocking raised again and again in public schools and libraries. Borderline porn such as the Brazilian actress Cicarelli Daniela sex-on-the-beach video have given legitimacy to such concerns. Although YouTube bans the distribution of pornography, much questionable content is available on the site. Due to the non-text and ever-changing nature of YouTube, parental controls and filters are often ineffective at blocking specific videos or portions of the site.