Introduction When we first encounter a scientific discipline, or a subject domain, we often would need to have a good standing point and as many signposts as possible to guide ourselves through the field. On the other hand, more experienced researchers and domain experts would need effective ways to track the development of their own fields and extract crucial signs of the dynamics of a scientific discipline (Bush, 1945). The World Wide Web (Web) has revolutionized the way we search for information. On today's Web we can easily access a vast amount of information on almost any subject. However, a profound challenge to many of us in the modern information society is to transcend the vast amount of information in scientific literature and access scientific knowledge at a higher level. The meta-knowledge, the knowledge of how particular knowledge structures have been perceived, should become an integral part of the scientific discipline involved, and it should be presented with simplicity and clarity for scholarly communication as well as public understanding. Domain visualization is an exciting field of study that addresses these q