The SCHEMAS Registry aims at providing a selected and annotated overview of metadata vocabularies and their use in application environments. Based on harvested metadata in RDF (Resource Description Framework), the registry allows users to explore links between "namespace schemas", which declare standard definitions of metadata terms, and "application profiles" – RDF statements about the use or adaptation of namespace terms for particular domains, services, or projects. Where instance metadata does not follow standard namespaces or explicit data models, this style allows implementors to assert an explicit mapping to standard terms. Registering profiles can help harmonize metadata usage in particular domains and, in the longer term, could provide a machineprocessable basis for automating crosswalks and conversions.