The Rhizomer platform is a Content Management System (CMS) based on a Resource Oriented Approach (RESTful) and Semantic Web technologies. It achieves a great level of flexibility and provides sophisticated content management services. All content is described using semantic metadata semi-automatically extracted from multimedia content, which enriches the browsing experience and enables semantic queries. A usable user interface is built on top of the CMS in order to facilitate the interaction with content and enhance it with the information provided by the associated semantic metadata. As an application scenario of the platform, its use in a media company where audio content is managed and its speech transcript semantically annotated is described.