Community Maps 3.0 is a participatory GIS prototype platform enabling communities of interests, governments and generic people to interact with multi-dimensional information spaces for retrieving and uploading geo-referenced information distributed in existing data sources as well as to discuss about the shared contents. MIMOSA extends Community Maps 3.0 with advanced information search facilities in order to enable people to interact with the 3D Community Map and to select the content to be visualized by using a clear and dynamic user interface. We will design and develop a proof of concept semantic engine that will exploit a multimodal domain ontology enabling the expression of the heterogeneous semantic contents related to the application domains, as well as the summaries of the multimedia data and external sources of information, to improve the users’ experience in browsing and searching data. A key component of the semantic engine will be a personalization module, which will combine the available integrated open data, the domain ontology and available private information characterizing users’ profiles and users’ interaction histories in order to manage a personalized shared information space.