Extensive Technology Review article about Evan Williams and Twitter
But Twitter seems to be it. The idea behind the service is simple: people compose 140-character updates about themselves, ostensibly answering the question "What are you doing?" Users can post their updates by text-messaging from cell phones, by logging on to the Twitter website, or by using desktop software such as instant-messaging tools. Messages (also known as twitters, twits, and tweets) can be private, sent only to friends or groups of friends, or they can appear on Twitter's home page for all to see. Twitter has been so successful that last April, Williams spun it out into its own company.