Analyzing content-level properties of the web adversphere

Advertising has become an integral and inseparable part of the World Wide Web. However, neither public auditing nor monitoring mechanisms still exist in this emerging area. In this paper, we present our initial efforts on building a content-level auditing service for web-based ad networks. Our content-level measurements - understanding the ad distribution mechanisms and evaluating location-based and behavioral targeting approaches - bring useful auditing information to all entities involved in the online advertising business. We extensively evaluate Google's, AOL's, and Adblade's ad networks and demonstrate how their different design philosophies dominantly affect their performance at the content level.