In this essay Martin Kurth identifies and probes four characteristics of metadata practice: (1) that metadata work typically deals with metadata in aggregates; (2) that metadata practitioners’ responsibilities consist of interpersonal, informational, and operational layers; (3) that metadata practitioners serve as translators who facilitate communication via information systems within and among communities of practice; and (4) that metadata practitioners build syntactic and semantic links that span community boundaries to serve the broader interests of interoperability and multidisciplinary collaboration. Kurth addresses an audience of metadata practitioners, information science educators, and library catalogers for the purposes of, first, identifying metadata practitioners’ unique contributions toward facilitating the use of digital information and, second, helping catalogers who are beginning to work with non-catalog metadata to relate metadata practice to cataloging practice.