This document discusses optimization of ad formats and placement to maximize revenue. It introduces some key terms like CPM (cost per mille, or cost per thousand impressions) and CTR (click-through rate). It then asks a series of questions about ad networks, sizes, and performance tests to gauge the reader's knowledge. The document recommends site designs that accept optimal ad sizes, make good use of space below page folds, and select ad networks that fit the site. It provides examples of a blogging site that earns $2-3 eCPM with 2 ads per page using AdSense, and $10-11 eCPM for longer user-generated content using multiple ad networks.