Drew Houston, founder and CEO of Dropbox, discusses lessons learned from Dropbox's experience as a startup. Some key points include: launching early with a minimum viable product to get user feedback; traditional marketing tactics like paid search were ineffective for Dropbox since it was serving a new market; encouraging word-of-mouth and viral growth through features like a referral program was much more effective, driving rapid user growth from just 100,000 to 4 million users over 15 months. The main lessons are to learn quickly from users, question conventional wisdom, and understand how the product fits for users in order to find the right growth strategies.