Social media platforms are important actors in the development of alcohol marketing techniques.While public health research has documented the activities of brands and consumers related to We argue that the changing character of user engagement with alcohol brands on Facebook can be related to changes in the platform architecture. Facebook is orchestrating a shift from exposure to engagement as its key advertising metric, and thus departing substantially from established mass media advertising paradigms. Effective policy responses to alcohol marketing in the digital era depend on a more rigorous examination of the marketing infrastructure of social media platforms.