This paper combines entrepreneurial behaviour and service innovation in order to investigate the use of the Idea Window the virtual tool planned for employee-driven service development in a healthcare organisation. The empirical study investigates the tool used as a method for supporting employees’ collaborative knowledge sharing in front-end of innovation in two study cases. Particularly, the research findings focus on how the virtual tool can be used for tackling the unknown - tacit knowledge, hidden possibilities, and initiatives in the context. The results are based on Idea Window entries and survey data collected in a Finnish hospital ward.