In the modern world, Twitter has changed the way we talk to each other, the way we share important news, and the way we learn about the world. You've probably heard of movie celebrities, politicians, and sports stars using Twitter to communicate with fans, but the social networking site has also done a lot to change the way ordinary people use the Internet. It's even changed the way we speak! Discover the story of Jack Dorsey, Twitter's co-founder, and how he helped to create one of the Internet's biggest successes. Learn how Jack and his friends came up with the ideas for the business that would change their lives—and the lives of so many Internet users—forever.