SDI4Apps is an EU project that is building a cloud-based Geospatial Linked Open Data platform for data integration, to bridge from the top-down managed world of Geospatial Information to the bottom-up user-driven mobile world of Linked Open Data voluntary initiatives and micro SMEs developing applications using the information. To ensure its success, SDI4Apps has ensured the active participation of user communities in its co-design and validation through the implementation of 6 varied pilots involved in environmental management across Europe. Successful implementation of the SDI4Apps user communities’ participation and their social validation is described in this paper. The social validation methodology has included development of specific criteria for measuring the platform‘s success, methods for multi-stakeholder social participation, analysis for internal and external communities and a clear set of indicators, which are now being measured during the validation process based on structured pilot scenarios. This robust stakeholders’ involvement methodology, which is central to SDI4Apps, is not only generating sustainable economic returns through the interface between the users, SMEs, policy makers and scientific communities, but guarantees a solid contribution to the knowledge-driven economy and environmental management across Europe.