This chapter focuses on dynamic taxonomies, a semantic model for the transparent, guided, user-centric exploration of complex information bases. Although this model has an extremely wide application range, it is especially interesting in the context of e-government because it provides a single framework for the access and exploration of all e-government information and, differently from mainstream research, is citizen-centric, i.e., intended for the direct use of end-users rather than for programmatic or agent-mediated access. This chapter provides an example of interaction and discusses the application of the model to many diverse e-government areas, going from e-services to disaster planning and risk mitigation.