Jack Dorsey is the creator, co-founder, and Chairman of Twitter and co-founder & CEO of Square. Originally from St. Louis, Jack's early fascination for mass-transit and how cities function led him to Manhattan and programming real-time messaging systems for couriers, taxis, and emergency vehicles. Throughout this work, Jack witnessed thousands of workers in the field constantly updating where they were and what they were doing; Twitter is a constrained simplification designed for general usage and extended by the millions of people who make it their own every day.Jack was recognized as one of Time Magazine's 100 most influential people and was named an "outstanding innovator under the age of 35" by MIT's Technology Review.