Pornography (often shortened to porn) is the portrayal of sexual subject matter for the exclusive purpose of sexual arousal. Pornography may be presented in a variety of media, including magazines, animation, writing, film, video, and video games. The term does not include live exhibitions like sex shows and striptease. The primary subjects of present-day pornographic depictions are pornographic models, who pose for still photographs, and pornographic actors who engage in filmed sex acts. Various groups within society have considered depictions of a sexual nature immoral, addictive, and noxious, labeling them pornographic, and attempting to have them suppressed under obscenity laws, censored or made illegal. Such grounds, and even the definition of pornography, have differed in various historical, cultural, and national contexts. Social attitudes towards the discussion and presentation of sexuality have become more tolerant in Western countries, and legal definitions of obscenity have become more limited, beginning in 1969 with Blue Movie by Andy Warhol, the first adult erotic film depicting explicit sexual intercourse to receive wide theatrical release in the United States. It was followed by the Golden Age of Porn (1969–1984), in which the best quality pornographic films became part of mainstream culture. A growing industry for the production and consumption of pornography developed in the latter half of the 20th century. The introduction of home video and the Internet saw a boom in the worldwide porn industry that generates billions of dollars annually. Commercialized pornography accounts for over US$2.5 billion in the United States alone, including the production of various media and associated products and services. The porn industry is between $10–$12 billion in the U.S. In 2006, the world pornography revenue was 97 billion dollars. This industry employs thousands of performers along with support and production staff. It is also followed by dedicated industry publications and trade groups, award shows, as well as the mainstream press, private organizations (watchdog groups), government agencies, and political organizations. Videos involving non-consensual content and cybersex trafficking have been hosted on popular pornography sites in the 21st century.