1) The document discusses lessons learned by Drew Houston, co-founder and CEO of Dropbox, about how they applied lean startup principles and grew Dropbox from 100,000 users to millions without traditional marketing. 2) Early on, Dropbox got feedback directly from users through a screencast and beta launch video which helped them learn. Their public launch focused on making users happy rather than traditional marketing plans. 3) Experiments with paid search, affiliates and other traditional tactics failed, but Dropbox continued growing through word-of-mouth as they encouraged sharing and referrals between users. 4) Dropbox's success showed that best practices don't always work and it's important to understand your market type and how your product fits