ABSTRACT
Wikipedia is a rhizomatic structure, a system of nodes and links without a fixed centre or underlying hierarchical pattern. It is the hyperlinks evident on every page that provide the main structure of the site, and allow for the possibility that any of the two and a half million articles may be directly connected up with any other. Hyperlinks provide the Wikipedia site's main structure, but alternative systems, useful for navigation or browsing, are also available. Authors are encouraged to assign categories to their articles, and at the bottom of most articles can be found a list of the various categories to which that particular article belongs. On Wikipedia's Main page there are a number of links to portals on broad topics such as Art, Biography and Mathematics, and each of these leads to other portals on narrower topics. Some Wikipedia articles take the form of lists in which each item links to its own article.
