Why Do Web Sites from Different Academic Subjects Interlink?

On the Web, hyperlinks have been used both to assess the impact of academic Web sites and to trace aspects of online informal scholarly communication. They are also used in Web information retrieval algorithms to identify important pages and to cluster pages by topic, both of which help in ranking search engine results. In this paper we investigate a type of link that is of particular interest for all of these applications: one that crosses subject boundaries. We took a sample of 586 linked pairs of domains in different UK academic sites, and extracted those that represented different subjects, resulting in 52 pairs of domains with different subjects. These were then grouped by the type of relationship between the source and target page. Over a third of the links formed a scholarly connection between similar subjects, but in 8% of cases dissimilar subjects also had a scholarly connection. Additionally, higher education teaching links were seen to form an extensive crossdisciplinary network, accounting for 19% of the links. A significant number of links (12%) also targeted non-subjectspecific general resources. The results suggest that mapping disciplinary collaboration on the Web should be feasible but that this process and topic identification in academic Webs would both be helped by the prior removal of key higher education teaching and popular general pages from the data set. These, and computing pages to a lesser extent, play a role more pernicious than ‘stop words’ in traditional information retrieval. The conclusions are of a qualitative rather than quantitative nature because of the small effective sample size, so an initial set of thousands of links would be required to remedy this.