Evolution of Wikipedia's Category Structure

TL;DR

This paper analyzes the evolution of Wikipedia's category structure from 2004 to 2008, revealing its stability and reorganization patterns, and how it correlates with article link networks.

Contribution

It provides a detailed analysis of Wikipedia's category system evolution and its relationship with article link structures over time.

Findings

The category network remained mostly stable with occasional reorganizations.

Clustering based on categories closely matches article link structures.

Pre-reorganization periods show deviations in clustering and link correlation.

Abstract

Wikipedia, as a social phenomenon of collaborative knowledge creating, has been studied extensively from various points of views. The category system of Wikipedia, introduced in 2004, has attracted relatively little attention. In this study, we focus on the documentation of knowledge, and the transformation of this documentation with time. We take Wikipedia as a proxy for knowledge in general and its category system as an aspect of the structure of this knowledge. We investigate the evolution of the category structure of the English Wikipedia from its birth in 2004 to 2008. We treat the category system as if it is a hierarchical Knowledge Organization System, capturing the changes in the distributions of the top categories. We investigate how the clustering of articles, defined by the category system, matches the direct link network between the articles and show how it changes over time. We find the Wikipedia category network mostly stable, but with occasional reorganization. We show that the clustering matches the link structure quite well, except short periods preceding the reorganizations.