The rapid establishment of third-generation distance learning environments, the so-called Web-based or tele-teaching environments, is nowadays a fact. The main means for the delivery of this new educational approach is the World Wide Web, and there are some good reasons for its use, such as its easy accessibility by many groups of learners. It also supports multiple representations of educational material and various ways of storing and structuring this information, as well as being powerful and easy to use as a publishing medium. Additionally, it has been widely accepted that the hyper-medial structure of the Web can support learning. Some researchers characterize the Web as an active learning environment that supports creativity. In addition to this, the Web encourages the exploration of knowledge and browsing, behaviors strongly related to learning. The associative organization of information in the Web is similar to that of human memory, and the process of information retrieval from the Web presents similarities to human cognitive activities (Tselios, Avouris, Dimitracopoulou, & Daskalaki, 2001).