Hence, an existence of multiple, specialised sets of metadata scattered both within and without the resource in question. There are two major types of metadata in terms of their placement with respect to the resource they annotate Internal - metadata are an integral part of the resource itself. It is possible to access a resource without ever stumbling upon a meta-data set it pertains to. Usually, information resources have at least one internal set of the metadata and several external ones, the existence of which may or may not be known to the authors of the resource in question. On the whole 'Pointers', 'Doors', 'Content indicators', 'Provenance indicators', 'Function indicators', 'Quality indicators', and 'Attention grabbers' tend to be located outside the information resources they are dealing with, whereas 'Navigation markers', 'Information decoders', and 'Structure indicators' reside mainly within such resources.
Metadata live in symbiotic relationship with the information they pertain to.
By contrast, the custom of annotating a printed book with the ISBN, the date of its publication, as well the location and name of the publisher is, in the late 20th c, a well entranched and 'fixed' arrangement. Metadata Production Metadata need to be talked about, understood and appreciated. Above all, however, they need to be put into regular, systematic, daily practice . Metadata Unresolved Issues Information, whether in an online or paper based format, is seldom homogeneous. Most of the time, it has a complex and multiply nested structure, with various parts being of different quality and of varying relevance to the purpose of the document in question.