This week, my colleague Denis Helic will present results from a recent collaboration investigating the usefulness of tag clouds at the IEEE SocialCom 2010 conference in Minneapolis, Minnesota, USA. In this paper (download pdf), we investigated if and to what extent tag clouds – a popular mechanism for interacting with social media – are useful for navigation.
While tag clouds can potentially serve different purposes, there seems to be an implicit assumption among engineers of social tagging systems that tag clouds are specifically useful to support navigation. This is evident in the large-scale adoption of tag clouds for interlinking resources in numerous systems such as Flickr, Delicious, and BibSonomy. However, this Navigability Assumption has hardly been critically reflected (with some notable exceptions, for example ), and has largely remained untested in the past. In this paper, we demonstrate that the prevalent approach to tag cloud-based navigation in social tagging systems is highly problematic with regard to network-theoretic measures of navigability. In a series of experiments, we will show that the Navigability Assumption only holds in very specific settings, and for the most common scenarios, we can assert that it is wrong.
While recent research has studied navigation in social tagging systems from user interface , ,  and network-theoretic  perspectives, the unique focus of this paper is the intersection of these issues. This paper provides answers to questions such as: How do user interface constraints of tag clouds affect the navigability of tagging systems? And how efficient is navigation via tag clouds from a network-theoretic perspective? Particularly, we first 1) investigate the intrinsic navigability of tagging datasets without considering user interface effects, and then 2) take pragmatic user interface constraints into account. We 3) will demonstrate that for many social tagging systems, the so-called Navigability Assumption does not hold and we will finally 4) use our findings to illuminate a path towards improving the navigability of tag clouds.
Here’s the abstract:
Abstract: It is a widely held belief among designers of social tagging systems that tag clouds represent a useful tool for navigation. This is evident in, for example, the increasing number of tagging systems offering tag clouds for navigational purposes, which hints towards an implicit assumption that tag clouds support efficient navigation. In this paper, we examine and test this assumption from a network-theoretic perspective, and show that in many cases it does not hold. We first model navigation in tagging systems as a bipartite graph of tags and resources and then simulate the navigation process in such a graph. We use network-theoretic properties to analyse the navigability of three tagging datasets with regard to different user interface restrictions imposed by tag clouds. Our results confirm that tag-resource networks have efficient navigation properties in theory, but they also show that popular user interface decisions (such as “pagination” combined with reverse-chronological listing of resources) significantly impair the potential of tag clouds as a useful tool for navigation. Based on our findings, we identify a number of avenues for further research and the design of novel tag cloud construction algorithms. Our work is relevant for researchers interested in navigability of emergent hypertext structures, and for engineers seeking to improve the navigability of social tagging systems.
The results presented in this paper make a theoretical and an empirical argument against existing approaches to tag cloud construction. Our work thereby both confirms and refutes the assumption that current tag cloud incarnations are a useful tool for navigating social tagging systems. While we confirm that tag-resource networks have efficient navigational properties in theory, we show that popular user interface decisions (such as “pagination” combined with reverse-chronological listing of resources) significantly impair navigability. Our experimental results demonstrate that popular approaches to using tag clouds for navigational purposes suffer from significant problems. We conclude that in order to make full use of the potential of tag clouds for navigating social tagging systems, new and more sophisticated ways of thinking about designing tag cloud algorithms are needed.
Here’s the full reference for the paper, and a link to the pdf as well as to preliminary slides:
Reference and PDF Download: D. Helic, C. Trattner, M. Strohmaier and K. Andrews, On the Navigability of Social Tagging Systems, The 2nd IEEE International Conference on Social Computing (SocialCom 2010), Minneapolis, Minnesota, USA, 2010. (download pdf) (related slides)
 M. A. Hearst and D. Rosner, “Tag clouds: Data analysis tool or social signaller?” in HICSS ’08: Proceedings of the Proceedings of the 41st Annual Hawaii International Conference on System Sciences. Washington, DC, USA: IEEE Computer Society, 2008.
 C. S. Mesnage and M. J. Carman, “Tag navigation,” in SoSEA ’09: Proceedings of the 2nd international workshop on Social software engineering and applications. New York, NY, USA: ACM, 2009, pp. 29–32.
 A. W. Rivadeneira, D. M. Gruen, M. J. Muller, and D. R. Millen, “Getting our head in the clouds: toward evaluation studies of tagclouds,” in CHI ’07: Proceedings of the SIGCHI conference on Human factors in computing systems. New York, NY, USA: ACM, 2007, pp. 995–998.
 J. Sinclair and M. Cardew-Hall, “The folksonomy tag cloud: when is it useful?” Journal of Information Science, vol. 34, p. 15, 2008. [Online]. Available: http://jis.sagepub.com/cgi/content/abstract/34/1/15
 N. Neubauer and K. Obermayer, “Hyperincident connected components of tagging networks,” in HT ’09: Proceedings of the 20th ACM conference on Hypertext and hypermedia. New York, NY, USA: ACM, 2009, pp. 229–238.