The paper presents a review of the sociological literature on platform work. In the first paragraph we introduce the concept of platform, the various types of platform and the specificities of the labour-based platforms. The second paragraph analyzes the main international and national statistical surveys aimed at mapping the platform work and the characteristics of workers, paying attention to both the methodological issues and the main research results. The last paragraph examines the contribution of sociology to the debate, identifying five streams of research–definition of the concept of labour, division of labour, social inclusion, social protection, collective organizing–that contribute to the definition of a research agenda.