Early Career Researcher. This chapter presents the case study of the Pay-Per-Use (PXU) Washing Machine by Ariston Digital. Sangiorgi and her co-author use the findings from her original research into Service Design to explore how her results apply to Communication Design. They suggest that Activity Theory can be a theoretical and analytical framework to evaluate and to design communication artefacts and interfaces: the evaluation of the service-communication system that happens through the digital washing machine interface can't be based upon the observation of the mere man-machine interaction, but it should include the evaluation and the comparison of the Activity Systems of the involved actors through the observation/reconstruction of their encounters during the installation, use and management of the washing machine itself. The PXU has been analyzed focusing on its interface and on two main service encounters that it enables - the installation of the PXU and the daily use of the machine - interviewing people directly or indirectly involved in the service encounters like users, technicians and the interface design team. The analysis of the case study showed how the evaluation of the PXU interaction models and communication system acquires new meanings when the analytical model, used to interpret the service interaction, is applied to real use situations (situated action) and when it compares information coming from the whole Activity Systems made up of: people, physical and conceptual artefacts, pre-existent and acquired behavioural models. This contribution was selected by Jorge Frascara, professor emeritus in Visual Communication Design, for his most recent book Designing Effective Communications: Creating Contexts for Clarity and Meaning. The book was selected by DT'