Twitter

         Twitter is an online social networking service and microblogging service that enables its users to send and read text-based messages of up to 140characters, known as "tweets".

         It was created in March 2006 by Jack Dorsey and launched that July. The service rapidly gained worldwide popularity, with over 500 million registeredusers as of 2012, generating over 340 million tweets daily and handling over 1.6 billion search queries per day. Since its launch, Twitter has become one of the ten most visited websites on the Internet, and has been described as "the SMS of the Internet." Unregistered users can read tweets, while registered users can post tweets through the website interface, SMS, or a range of apps for mobile devices.

         Twitter Inc. is based in San Francisco, with additional servers and offices in New York City, Boston, and San Antonio.

(Reference: http://en.wikipedia.org/wiki/Twitter)