Twitter is a global social networking platform that allows its users to send and read 140-character messages known as “tweets”. It enables registered users to read and post their tweets through the web, short message service , and mobile applications. As a global real-time communications platform, Twitter has more than 400 million monthly visitors and 255 million monthly active users around the world. Twitter’s active group of registered members includes World leaders, major athletes, star performers, news organizations, and entertainment outlets. It is currently available in more 35 languages. Twitter was launched in 2006 by Jack Dorsey, Evan Williams, Biz Stone and Noah Glass. Twitter is headquartered in San Francisco, California, USA, with local offices in Atlanta, Austin, Boston, Boulder, Chicago, Detroit, Los Angeles, New York, Sunnyvale and Washington. Twitter's international offices are located in Amsterdam, Berlin, Dublin, London, Madrid, Paris, Rio de Janeiro, Sao Paulo, Singapore, Sydney, Seoul, Tokyo, Toronto and Vancouver.