This document discusses how startups can leverage big and small data to improve their business. It recommends that startups collect usage, purchase, and interaction data to gain insights. The same data can provide different views to optimize aspects like aesthetics, fraud detection, marketing, and pricing. Startups should experiment by conducting A/B tests and act on what the data shows rather than vanity metrics. More sophisticated statistical and machine learning algorithms can help understand metrics when experimenting is not possible, but correlation does not imply causation. Automating business reactions to real-time data is ideal, or reacting to appropriate data manually using visual summaries.