This document provides an overview of how advertising works on the internet and the key players involved. It discusses how brands work with digital agencies to plan and handle online advertising campaigns. Digital agencies strategize advertisement placement, create ads that meet standards, bid for ad space on various platforms, publish the ads, track performance, and analyze results to modify campaigns as needed. The goal is to use new technologies to effectively reach customers and target specific regions and demographics. A brief history of digital and viral advertising is also mentioned.