What Is Metadata

The one-phrase definition of “metadata” – “data about data” – is too broad to have practical value. However, the uses of metadata itself across all of computing, and the ways in which it is represented, are so numerous and diverse that it would be hard to find two practitioners who think about it in exactly the same terms. An inspection of Wikipedia’s article on the subject,1 especially the accompanying discussion, will make it clear that the topic has grown to the point where its editors believe that the article has become too large and unwieldy – and yet it barely touches on the themes that are of specific relevance to this book.