Interesting, and I think accurate, observation by Stuart Sutton in his review of Cilla Caplan's new book on metadata for librarians.

While we frequently hear the naive remark (not infrequently from people who should know better) that libraries have been all about metadata from their beginnings and that librarians have a good grip on metadata principles and practices, you don't have to scratch much below the surface of the notion of metadata to discover the true state of affairs. While some librarians have bridged the gap between a relatively well organized world of tightly federated systems and practices in generating bibliographic records (unquestionably metadata) and the far less cohesive universe of metadata being generated by many of today's cultural heritage institutions and other public and private sector entities, far too many librarians haven't got a metadata clue. Many gaze across the emerging metadata landscape like deer in the headlights of an automobile—at best baffled and more frequently absolutely frightened. The unruly, untidy nature of this landscape offends the sensibilities of those more at ease with well articulated principles and practices. For many, the metadata landscape appears to be strewn with defunct initiatives (all with varying degrees of bright promise in their infancy) and myriad mindless, uninteroperable variations on the same themes. [Metadata Fundamentals for All Librarians]