This document provides an overview of programmatic buying and the digital advertising landscape. It discusses how demand-side platforms (DSPs) allow buyers to purchase inventory from ad exchanges through real-time bidding (RTB). Supply-side platforms (SSPs) enable publishers to manage and maximize revenue from their ad impression inventory. It also describes how data management platforms (DMPs) collect, organize and target audiences using first-party, second-party and third-party data. Dynamic creative optimization (DCO) delivers customized creatives to each audience segment in real-time.