Understanding what metadata is and how it helps to better organize your knowledge base - digi-libris

Metadata is data about data[2] which helps to describe the content or characteristics of an electronic or physical object. The author of a scientific paper, the publisher of a book, the copy right of a photograph, the scene of a painting, the theme of a song and the architect of a 2500BC pyramid are all valid metadata or attributes of the item concerned. They serve to classify it in your private search engine or to share it with colleagues or even with the world at large.

This latter point deserves special attention, because different users may require different pieces of data. Art critiques, veterinaries, physicists and lawyers use different jargons, yet all download regularly content from other domains to integrate in their own knowledge base, preferably without manual intervention, based solely on embedded metadata such as title, author, subject, description, keywords etc., provided documents are well-behaved.

While there are dozens of metadata standards[3] belonging to dozens of fraternities, each with its own vocabulary[4], none covering all needs of all users. A student may need data he can use to generate citations and an engineer would search his collection of documents by technical criteria.

The digi-libris pragmatic solution to this dilemma:

An individually extensible and universally applicable metadata set.

It builds on the widely used Dublin Core standard[5] (minus refinements) plus an unlimited number of customizable attribute/value pairs for the data. Consider it as an alternative Dublin Core application profile (DCAP) for individuals who may or may not have to rely on a single standard issued by an institution. One does not exclude the other! For the exchange of Metadata with third parties it relies on Adobe’s widely accepted XMP[6] technology. This is the format already implemented in PDF documents and it includes a placeholder for arbitrary or custom variables (pdfx).