Founder, TwitterRank: 44Why he matters: When we say You have questionable judgment, Williams's Twitter may be a case in point. Twitter gives each user a webpage, where short text updates (known as "tweets") can be posted to the site via IM, SMS, or blogging tools. The result is a torrent of short notes and inane observations (from "Feeling sick today" to "I'm in the bathroom!") pouring in from buddies throughout the day.
Fans say Twitter is an invaluable way to stay in the loop. We're not so sure. Twitter is either a major new communications platform or the next overhyped Friendster. Which will it be? Ask us again next year.
Meet 50 Who Matter winner Gina Bianchini. Her site, Ning, lets anyone be a social networking mogul. (more) 
