New and unprecedented sources of geographic information have recently become available in the form of user-generated Web content. The integration and application of these sources, often termed volunteered geographic information (VGI), offers multidisciplinary scientists an unprecedented opportunity to conduct research on a variety of topics at multiple spatial and temporal scales. Since applications generating VGI are not often designed specifically for data production or analytical purposes, the Action aims at the following to fill this gap, recognizing the potential value of these sources to the EU in citizen-based decision making by: 1) define VGI sources, share and develop data retrieval software, assess VGI quality, 2) define standardization criteria for interoperability with other datasets, 3) identify applications and transfer these applications to business implementation (market analysis, risk management, advertising, etc.). The Action targets fundamental scientific and technological advances by establishing a European network of excellence on GeoWeb technologies.The Action will focus on VGI and gather efforts carried out in an innovative and under-exploited field of Web research and knowledge production. VGI is particularly relevant as it provides information of citizens’ preferences and concerns and is an alternative source of knowledge in a context where governments are putting less resources in data collection.