This paper describes a BBC project to unify Archive and Production workspaces, during which numerous issues with managing different types of metadata and Knowledge Organisation Systems (KOSs) were encountered. Integrating diverse content silos requires bringing together not simply the assets, but also the metadata used to manage those assets. The paper summarises the theoretical background to the project, the BBC's ‘information ecosystem’, and the user research and requirements-gathering exercises undertaken. Much work on developing metadata crosswalks has been at the heading or label level, and not based on semantic analysis of the content of the labelling or description. However, such semantic analysis needs to be undertaken when mapping diverse taxonomies, thesauri, and keyword lists and, in practice, often needs to balance preservation of local or specialised terminology with accessibility for general users. Just as metadata about content permits the organization of that content, so metadata about metadata (parametadata, or meta-metadata) permits the organization of metadata, enabling end users to make informed browse and navigation choices. Increasingly, in order to integrate content, different KOSs, such as taxonomies and ontologies, need to be related. The paper concludes by summarising the ways in which problems that arose during the integration project were resolved, and how policies for managing parametadata, subjective metadata, and semantic-level mapping were developed.