Followers: 2.2 million
Sample tweet: "5 Mobile App Trends You Can't Ignore"
For the few on Twitter who are still unfamiliar with Mashable, the social-media powerhouse founded by Pete Cashmore, consider this your formal introduction. Since founding the site in 2005 at the age of 19, Cashmore has nurtured it into one of the largest sources for social-media, digital and tech news on the Web.