The Gatekeeper Dynamic: Updating Lewin's Gatekeeping Theory for the Age of Digital Advertising Ecosystems (Version 2.0)

This paper introduces the Gatekeeper Dynamic as a modern extension of Kurt Lewin’s Gatekeeping Theory, redefined for digital advertising ecosystems. It explains how platforms such as Google retain advertising spend within their own environments by controlling audience attention, data, and measurement tools. Alphabet’s advertising channels are used as a case study to show how Search, YouTube, and Display operate as ecosystem “gates.”

Version 2 expands the framework to include conversational artificial intelligence (AI) as the next form of gatekeeping. Unlike traditional search engines, AI agents personalize, filter, and constrain search results, collapsing choice into synthesized outputs that shape what consumers see and trust. The paper concludes that gatekeeping now lies at the intersection of platforms and AI, with major implications for advertisers, policymakers, and researchers.