Wikipedia
PostYourBook
PostYourBook (or PostYourBook.com) is a social networking website made by college students for college students to buy and sell their textbooks to each other.
Postyourbook.com was created in December 2010 by a self-proclaimed entrepreneur Josh Hiekali for Santa Monica College students to post their textbooks online and sell them to each other for their desired price. PostYourBook.com eliminated the need for a bookstore to serve as the middle man.
After about a year in existence, PostYourBook.com was live at over 160 universities nationwide, with approximately 150,000 active users. The website is currently open to more than 250 major universities nationwide, and services over 250,000 students each semester.