Square is a mobile payment system that allows individuals and small businesses to accept credit card payments through a small card reader that plugs into a smartphone or tablet. Founded in 2009 by Jack Dorsey, Square has experienced rapid growth, processing over $2-10 million per week in payments after signing up over 100,000 users in its first few months. Square aims to make accepting payments easier by eliminating the need for cash registers or bank accounts. Users simply download the Square app, register for a free card reader, and are able to start accepting payments with low transaction fees.