In the 2000s, as digital formats are becoming the prevalent way of storing data and information, metadata is also used to describe digital data using metadata standards.
Metadata assists users in resource discovery by "allowing resources to be found by relevant criteria, identifying resources, bringing similar resources together, distinguishing dissimilar resources, and giving location information." Metadata of telecommunication activities including Internet traffic is very widely collected by various national governmental organizations.
This data is used for the purposes of traffic analysis and can be used for mass surveillance. Although the "meta" prefix (from the Greek preposition and prefix μετά-) means "after" or "beyond", it is used to mean "about" in epistemology.
According to Ralph Kimball metadata can be divided into 2 similar categories: technical metadata and business metadata.
Technical metadata corresponds to internal metadata, and business metadata corresponds to external metadata. On the other hand, NISO distinguishes among three types of metadata: descriptive, structural, and administrative.
Tools such as controlled vocabularies, taxonomies, thesauri, data dictionaries, and metadata registries can be used to apply further standardization to the metadata.