Metadata is 'information about data'. That is, metadata describes some aspect of data on the Internet. There has been significant activity recently on defining the semantic and technical aspects of metadata for use on the Internet and the WWW. A number of metadata sets have been proposed together with the technological framework to support the interchange of metadata. These initiatives will have a dramatic effect on how the Web is indexed and will improve the discovery of resources on the Internet by a significant factor. This paper discusses the issue of the provision of a mechanism for a registry of metadata schemas. A proposal, using an enhanced version of PICS is presented. This will enable global interoperability across various extensible metadata sets.