This work presents the OntoCollab system for research and demonstration scenarios, which semantically supports users in describing documents and refining search queries. Furthermore, a user can navigate through the company's tag clouds. The underlying technology is based on Topic Maps. The semantic expressiveness is sufficient to represent a thesaurus, facet classification, and part-whole relationships. The system consists of a Topic Map, an evaluation system, a suitable client user interface, and an XML database. The prototype has been successfully implemented. The application scenarios demonstrate that terminology and product structures can be semantically integrated, making it easier to describe information objects and find them more accurately.