This document discusses how clickstream data can be used to understand audiences, target them in media buys, and optimize digital advertising campaigns. It explains that clickstream data provides insights into audience behaviors across websites that can be used to define customer segments. These insights and segments can then power audience targeting in media buys. Finally, clickstream data ties digital campaigns to brand-related metrics that allow optimization to increase return on investment. The document advocates connecting these three stages - understanding audiences through analytics, targeting the right audiences, and optimizing campaigns - to improve performance.