Goodreads: Otis and Elizabeth Chandler

As a young programmer in the mid-2000s, Otis Chandler watched as dozens of niche web sites began to take off. When he decided to launch his own site just for book lovers, a respected colleague told him there was "probably not a very big market there." Otis figured he might prove him wrong, and in 2007, launched Goodreads, a book catalog and review site that he coded from his LA apartment. His soon-to-be-wife Elizabeth joined the project, and they slowly built a following—without an office, a business model, or a single employee. In 2013, Goodreads sold to Amazon for an undisclosed sum; and today, it's the world's largest site for readers, with 125 million users.