Williams has a knack for figuring out how people want to keep in touch—even before they seem to know it themselves. In 1999 he launched Blogger, a service that allows people to post their every thought online. That turned anyone with a computer into a global publisher. After selling Blogger to Google, Williams created a podcasting startup named Odeo that didn’t take off. But in the meantime, Jack Dorsey, an employee at Williams’ company, came up with Twitter. Twitter has popularized microblogging, the streams of short posts people write to groups of friends. During the past two years, the popularity of Twitter has exploded, as people turn to new ways to stay in touch.