This article discusses how Participatory GIS (PGIS) can be improved by applying current start-of-the-art computing technologies, in particular high performance computing technology. The discussion covers the methods and tools for the four types of space-time collaboration situations (different place/time). While the four types are all addressed, the focus is directed to the same time, different place collaboration which is prone to pose more challenges for time-critical services. A design of a high performance Grid-enabled PGIS for this scenario is presented along with pilot implementations for an emergency evacuation problem.