Abstract: Buying stage determination techniques in a digital medium environment are described to model and control user interaction with a service provider to purchase a good or service through identification of stages in a buying cycle associated with users. Usage data is obtained that at least describes interactions by one or more users with the service provider that occurred during previous sessions. The marketing interactions in the obtained usage data are classified and quantified for respective said users using one or more features. Generation of a model of the stages of the buying cycle is controlled using the quantified usage data. The model is configured to identify a stage in the buying cycle that is associated with a respective said user, which is usable to control further marketing interactions supported for that user.