["The American Journal of Economics and Sociology, EarlyView. ", "\nABSTRACT\nOver the past two decades, digital economic activity has experienced rapid development. In China, it accounts for 40% of GDP, with the number of internet and mobile users ranking among the highest in the world. In the United States, the digital economy accounted for only 10% of GDP when last measured in 2022, but it is growing rapidly. Although digital platforms represent a massive growth potential, they have a dark side. By leveraging economies of scale, network effects, and data monopolies, this cutting edge of economic development concentrates ownership and wealth, while it suppresses competition, limits innovation, and impairs consumer rights. Since economic inequality leads to social instability, platform monopolies have created novel problems that cannot easily be solved with existing methods. Since the surplus value created by digital platforms arises from social interaction rather than conventional factors of production (labor, capital, and land), the capture of this new form of value requires a new theoretical framework. In this article, we examine whether the analytic tools first formulated by Henry George may be the best method of understanding and responding to the challenge of platform monopolies. George viewed monopoly as a systemic problem when it arises from the privatization of socially created value. Although China has introduced the world's first antitrust guidelines for the platform economy, addressing platform monopoly requires more than regulation. Economic interventions are also needed. We explore here what those interventions might be.\n"]