Within the last three years, Google has acquired YouTube and DoubleClick and has attempted to control part of Yahoo!'s search advertising business. Two of the deals have not raised antitrust concerns by competition authorities. I review these deals with a focus on consumer welfare. Consumers are...

Media firms sometimes allow consumers to pay to remove advertisements from an advertisement-based product. We formally examine an ad-based monopolist s incentives to introduce this option. When deciding whether to introduce the option to pay, the monopolist compares the potential direct revenues...

We propose a duopoly model of competition between internet search engines endowed with different technologies and study the effects of an agreement where the more advanced firm shares its technology with the inferior one. We show that the superior firm enters the agreement only if it results in...