The first article in this series (Vol 11(11): 759-63) described the development of the ACTION project, an information technology-based initiative designed to enhance the quality of life for family carers and older people, and the second article (Vol 11(12): 827-31) considered how the usability of the ACTION system as a whole was evaluated. This, the third article, presents a case study which describes in more detail the impact of the ACTION project on the lives of both a family carer (Rolf) and his wife (Kerstin), and on the technical worker (Thomas) who helped Rolf and Kerstin to learn to use the ACTION system. The impact of the intervention is assessed using two broad sets of criteria: (1) those relating to the PREP (Preparedness, Enrichment, Predictability) model of nursing interventions, and (2) those relating to the wider implications of participation in a research and development project of this nature.