Karen Coyle's article "Understanding the Semantic Web: bibliographic data and metadata" may be of wide interest in libraries. It is about 30 p. and is the full content of _Library Technology Reports_ v. 46, issue 1, Jan. 2010. (This is available online at Yale via Gale Cengage Academic One File.) The first chapter (of two) is available online at http://alatechsource.metapress.com/content/p3022442071g7655/fulltext.pdf
Coyle briefly places traditional (i.e. Panizzi and since) library bibliographic data in its contemporary context (Internet, etc.) and calls for changing our traditions to fit the new context. She then discusses several steps necessary to make the change from what is more or less textual descriptions (e.g. catalog cards, MARC records) to sets of data elements that can be processed by computers (e.g. linked data in the semantic web.)
Overall, this is a nice brief on library metadata and its relation with the semantic web, RDF (Resource Description Framework), identifiers, and linked data. If you already know this, Coyle's article is worth the review. If you don't already know this, Coyle's article is a good place to begin.