Folksonomy

A folksonomy is a system of classification derived from the practice and method of collaboratively creating and managing tags to annotate and categorize content; this practice is also known as collaborative tagging, social classification, social indexing, and social tagging. Folksonomy, a term coined by Thomas Vander Wal, is a portmanteau of folk and taxonomy. Vander Wal explains some of the characteristics of folksonomies by identifying two types: broad and narrow. A broad folksonomy is one in which multiple users tag particular content with a variety of terms from a variety of vocabularies, thus creating a greater amount of metadata for that content. A narrow folksonomy, on the other hand, occurs when a few users, primarily the content creator, tag an object with a limited number of terms. While both broad and narrow folksonomies enable the searchability of content by adding textual description - or access points - to an object, a narrow folksonomy does not have the same benefits as a broad folksonomy, which allows for the tracking of emerging trends in tag usage and developing vocabularies. Folksonomies became popular on the Web around 2004 as part of social software applications such as social bookmarking and photograph annotation. Tagging, which is one of the defining characteristics of Web 2.0 services, allows users to collectively classify and find information. Some websites include tag clouds as a way to visualize tags in a folksonomy. A good example of a social website that utilizes folksonomy is 43 Things. However, tag clouds visualize only the vocabulary but not the structure of folksonomies, as do tag graphs.

An empirical analysis of the complex dynamics of tagging systems, published in 2007, has shown that consensus around stable distributions and shared vocabularies does emerge, even in the absence of a central controlled vocabulary. For content to be searchable, it should be categorized and grouped. While this was believed to require commonly agreed on sets of content describing tags (much like keywords of a journal article), recent research has found that, in large folksonomies, common structures also emerge on the level of categorizations. Accordingly, it is possible to devise mathematical models of collaborative tagging that allow for translating from personal tag vocabularies (personomies) to the vocabulary shared by most users.