Dropbox was founded in 2007 by Drew Houston as a file sharing and storage application that allows users to easily sync and access files across devices. It gained popularity through word-of-mouth and viral marketing. While Dropbox saw strong growth and many new users, Houston faced dilemmas around whether to segment users and how to balance adding new features while maintaining simplicity. Competitors like Mozy and Carbonite also posed challenges to Dropbox's business model and growth.