Square

Square is a revolutionary service that enables anyone to accept credit cards with an iPhone, iPad, or Android device. It's simple to sign up, and there’s no contracts or monthly fees involved. Square has 1 million merchants and processes over 2 billion dollars per year. Square was co-founded by in 2009 by Jack Dorsey, who is well known for founding Twitter. Square is headquartered in San Francisco. Fast Company Magazine considers Square the 5th most innovative company in the world behind Apple, Facebook, Google, and Amazon: http://www.fastcompany.com/most-innovative-companies/2012/full-list.