After a brief stint at the Missouri University of Science and Technology, Dorsey transferred to New York University. In the tradition of computer science entrepreneurs such as Bill Gates, Steve Jobs and Mark Zuckerberg, he dropped out of college before receiving his degree. Instead, Dorsey moved to Oakland, California, and in 2000 started a company offering his dispatch software through the Web. Shortly after starting his company, Dorsey came up with the idea for a site that would combine the broad reach of dispatch software with the ease of instant messaging, and approached a now-defunct Silicon Valley company called Odeo to pitch the concept. "He came to us with this idea: 'What if you could share your status with all your friends really easily, so they know what you're doing?'" said Biz Stone, a former Odeo executive. Dorsey, Stone and Odeo co-founder Evan Williams started a new company, called Obvious, which later evolved into Twitter. Within two weeks, Dorsey had built a simple site where users could instantly post short messages of 140 characters or less, known in Twitter parlance as "tweets."
On March 21, 2006, Jack Dorsey posted the world's first tweet: "just setting up my twttr." Dorsey was named the company's chief executive officer. Co-founder Evan Williams replaced Dorsey as Twitter's CEO in October 2008, with Dorsey staying on as company chairman. On March 28, 2011, Dorsey returned to twitter as Executive Chairman.
