Information and communication technologies have played a fundamental role in teaching and learning for many years. Technologies, such as radio and TV, were used during the 50s and 60s for delivering instructional material in audio and/or video format. More recently, the spread of computer-based educational systems has transformed the processes of teaching and learning (Squires, Conole, & Jacobs, 2000). Potential benefits to learners include richer and more effective learning resources using multimedia and a more flexible pace of learning. In the last few years, the emergence of the Internet and the World Wide Web (WWW) have offered users a new instructional delivery system that connects learners with educational resources and has led to a tremendous growth in Web-based instruction. Web-based instruction (WBI) can be defined as using the WWW as the medium to deliver course material, manage a course (registrations, supervision, etc.), and communicate with learners. A more elaborate definition is due to Khan (1997), who defines a Web-based instructional system (WIS) as “...a hypermedia-based instructional program which utilises the attributes and resources of the World Wide Web to create a meaningful learning environment where learning is fostered and supported.” Relan and Gillani (1997) have also provided an alternative definition that incorporates pedagogical elements by considering WBI as “...the application of a repertoire of cognitively oriented instructional strategies within a constructivist and collaborative learning environment, utilising the attributes and resources of the World Wide Web.” Nowadays, WISs can take various forms depending on the aim they serve: • Distance-learning (DL) systems’ goal is providing remote access to learning resources at a reduced cost. The concept of DL (Rowntree, 1993) is based on: (i) learning alone, or in small groups, at the learner’s pace and in their own time and place, and (ii) providing active learning rather than passive with less frequent help from a teacher. • Web-based systems, such as intelligent tutoring systems (Wenger, 1987), educational hypermedia, games and simulators (Granlund, Berglund, & Eriksson, 2000), aim at improving the learning experience by offering a high level of interactivity and exploratory activities, but require a significant amount of time for development. The inherent interactivity of this approach leads learners to analyse material at a deeper conceptual level than would normally follow from just studying the theory and generates frequently cognitive conflicts that help learners to discover their possible misunderstandings and reconstruct their own cognitive models of the task under consideration. • Electronic books provide a convenient way to structure learning materials and reach a large market (Eklund & Brusilovsky, 1999). • Providers of training aim to offer innovative educational services to organisations for workplace training and learning, such as to supplement and support training in advance of live training, update employee skills, develop new skills.