This document discusses online advertisement and the AdWords problem. It begins by describing traditional advertising like posters, magazines and billboards that charge per impression, then describes how online ads use targeting and metrics like clicks. It explains that AdWords is Google's advertising system where advertisers bid on keywords and the highest bidder's ad appears. The document defines the AdWords problem and algorithms like greedy and balance that aim to maximize revenue by sorting ads by expected revenue rather than bid. It provides an example showing the balance algorithm can achieve a better competitive ratio than greedy. Finally, it mentions implementing this on an open advertising dataset.