Internet advertising is the growth engine that sustains the availability of free applications such as YouTube and MySpace. Without Internet advertising revenues, many believe that innovators would cease to develop these immensely popular programs. On the flipside, advertisers will only advertise on Web pages that have a strong following or that they believe have the potential to attract many visitors. What would happen if a new entity were created that controlled most of the ads appearing on the Internet? The Google-DoubleClick merger may do just that. Given the important role of advertising in Internet innovation, how should federal antitrust officials decide on the important issues involved in assessing the merits of the merger, such as the relevant market and barriers to entry? How should they assess issues specifically related to Internet advertising, such as the effect of one company’s control of significant consumer data? By focusing on the potential costs and benefits of the Google-DoubleClick merger, panelists at this Joint Center conference will examine the economics of Internet advertising and the role of such advertising in internet competition.