Content Structure

A sprawling, amorphous subject ... some will go with 'semantic content' for Semantastic site.


Faceted search, also called faceted navigation or faceted browsing, is a technique for accessing information organized according to a faceted classification system, allowing users to explore a collection of information by applying multiple filters. A faceted classification system classifies each information element along multiple explicit dimensions, called facets, enabling the classifications to be accessed and ordered in multiple ways rather than in a single, pre-determined, taxonomic order.[1]

Facets correspond to properties of the information elements. They are often derived by analysis of the text of an item using entity extraction techniques or from pre-existing fields in a database such as author, descriptor, language, and format. Thus, existing web-pages, product descriptions or online collections of articles can be augmented with navigational facets.

A faceted classification system allows the assignment of an object to multiple taxonomies (sets of attributes), enabling the classification to be ordered in multiple ways, rather than in a single, predetermined, taxonomic order.

A facet comprises "clearly defined, mutually exclusive, and collectively exhaustive aspects, properties or characteristics of a class or specific subject". For example, a collection of books might be classified using an author facet, a subject facet, a date facet, etc.

Arlene Taylor gives a good visual description of Faceted Classification. She states, “If one thinks of each of the faces of a cut and polished diamond as a facet for the whole diamond, one can picture a classification notation that has small notations standing for subparts of the whole topic strung together to create a complete classification notation”.

Classification Schemes

In metadata a classification scheme is an arrangement of kinds of things (classes) or groups of kinds of things. It is often represented as a hierarchical structure and accompanied by descriptive information of the classes or groups.

A classification scheme is intended to be used for an arrangement or division of individual objects into the classes or groups. The classes or groups are based on characteristics which the objects (members) have in common ...

Some quality criteria for classification schemes are:

Whether different kinds are grouped together. In other words whether it is a grouping system or a pure classification system. In case of grouping, a subset (subgroup) does not have (inherit) all the characteristics of the superset, which makes that the knowledge and requirements about the superset are not applicable for the members of the subset.

Whether the classes have overlaps.

Whether subordinates (may) have multiple superordinates. Some classification schemes allow that a kind of thing has more than one superordinate others don't. Multiple supertypes for one subtype implies that the subordinate has the combined characteristics of all its superordinates. This is called multiple inheritance (of characteristics from multiple superordinates to their subordinates).

Whether the criteria for belonging to a class or group are well defined.

Whether the kinds of relations between the concepts are made explicit and well defined.

Whether subtype-supertype relations are distinguished from composition relations (part-whole relations) and from object-role relations.

A folksonomy is a system of classification derived from the practice and method of collaboratively creating and translating tags to annotate and categorize content;[1][2] this practice is also known as collaborative tagging,[3] social classification, social indexing, and social tagging.

In information systems, a tag is a non-hierarchical keyword or term assigned to a piece of information (such as an Internet bookmark, digital image, or computer file). This kind of metadata helps describe an item and allows it to be found again by browsing or searching.

Tags are generally chosen informally and personally by the item's creator or by its viewer, depending on the system.


The Modular Unified Tagging Ontology (MUTO) is an ontology for tagging and folksonomies. It is based on a thorough review of earlier tagging ontologies and unifies core concepts in one consistent schema. It supports different forms of tagging, such as common, semantic, group, private, and automatic tagging, and is easily extensible.

This website is an attempt to consistently define key terms related to tagging and folksonomies. The definitions form the basis of the Modular Unified Tagging Ontology (MUTO) that is specified at:

TagOnt? is an OWL ontology describing the concept of tagging (folksonomy), i.e. it is basically a formal description of tags, resources and their relations.

As Knowledge

See KnowledgeBase


Also See

Last modified 18 months ago Last modified on 10/25/2015 05:59:47 PM