15. Stamped

Founder: Robby Stein, Bart Stein and Kevin Palms

Founded: 2011

Based in: New York

Stamped is a mobile app that lets users bookmark his/her favorite songs, movies, restaurants, books and more. It gives the user a quick update on everything as it lets people follow celebrities and other users from whom all recent tastes and trends can be discovered. Ellen DeGeneres, Ryan Seacrest, Justin Bieber, The New York Times, Columbia Records, CrunchFund, Eric Schmidt, ShoeDazzle's Brian Lee, and Pandora CTO Tom Conrad are all its investors.

14. Square

Founder: Jack Dorsey

Founded: February 2009

Based in: San Francisco, CA

Square is a mobile payment solution provider, it is a credit card swiper that can be attached to mobile devices which can be used to make and receive payments on the go. The founder, Jack Dorsey is considered to be one of the most innovative entrepreneurs in the world and he is also often compared to Steve Jobs. The company also had raised $166 million.