Computer programmer and entrepreneur. Born November 19, 1976, Jack Dorsey is best known as the creator of Twitter. He grew up in St. Louis, Missouri. Dorsey became interested in computers and communications at an early age and began programming while still a student at Bishop DuBourg High School. He was fascinated by the technological challenge of coordinating taxi drivers, delivery vans and other fleets of vehicles that needed to remain in constant, real-time communication with one another. When he was 15, Dorsey wrote dispatch software that is still used by some taxicab companies today.