Since the introduction of Geographic Information Systems (GIS) into archaeology in the 1980s, most of the problems that archaeologists encountered in the course of utilising the geospatial technologies had not been explained anywhere and thus had to be resolved only through a redundant process of trial and error. In order to share knowledge and experience on GIS applications to archaeology, a self-motivated group of Japanese researchers inaugurated an online-based academic forum, Archaeo-GIS Workshop (AGW), in 2007. This paper reviews concepts and activities of the AGW in the past three years and then discusses current agendas and future tasks. The AGW employs two complementary communication channels: online social networking services and offline hands-on workshops. The administration and operation of the AGW relies exclusively on the spirit of volunteerism and financial self-sufficiency. The AGW welcomes wider audiences across disciplinary boundaries and encouraged more members to actively participate in the events and projects.