According to the literature, the term "information visualization" is referred to in a variety of contexts of meaning. In general, psychologists use the term to signify a representational mode (as opposed to verbal descriptions of subject-matter content) used to illustrate in a visual-spatial manner, for example, objects, dynamic systems, events, processes, and procedures. In this regard, the term "information visualization" is an umbrella term for all kinds of visualizations. Here, the term is used in the context of processing, comprehension, and retention of information in static, animated, dynamic, and interactive graphics (Ploetzner & Lowe, 2004; Schnotz, Picard & Hron, 1993). However, computer scientists define the term in a more narrow sense and referred to it as “the use of computer-supported, interactive, visual representation of abstract nonphysically based data to amplify cognition" (Card, Mackinlay & Shneiderman, 1999, p. 6). In computer science, information visualization is a specific technology. According to Carr (1999), information visualization of abstract data is of particular importance for information retrieval if the underlying data set is very large (e.g. like in the case of searching for information on the World Wide Web) and the goals of the user with regard to information retrieval are not easily quantifiable. Research in this context refers to information visualization as a technology for fostering the recognition of structures in abstract data and supporting information retrieval.