Navigational efficiency of broad vs. narrow folksonomies

Although many social tagging systems share a common tripartite graph structure, the collaborative processes that are generating these structures can differ significantly. For example, while resources on Delicious are usually tagged by all users who bookmark the web page cnn.com, photos on Flickr are usually tagged just by a single user who uploads the photo. In the literature, this distinction has been described as a distinction between broad vs. narrow folksonomies. This paper sets out to explore navigational differences between broad and narrow folksonomies in social hypertextual systems. We study both kinds of folksonomies on a dataset provided by Mendeley - a collaborative platform where users can annotate and organize scientific articles with tags. Our experiments suggest that broad folksonomies are more useful for navigation, and that the collaborative processes that are generating folksonomies matter qualitatively. Our findings are relevant for system designers and engineers aiming to improve the navigability of social tagging systems.