This study focused on the integration of a Web shell for supporting emergent-collaboration activities in six graduate courses (115 students) in the Tel-Aviv University School of Education. Emergent-collaboration is the process by which group configurations and transactional patterns evolve among participants during the course of learning. The research questions addressed in the study were related to: (a) the didactic modes that have been devised for supporting emergent-collaboration learning processes, and (b) the extent of participation of students and teachers in Web- supported emergent-collaboration learning processes. Six Web-based instructional modes evolved during the study supporting: social interaction; critical group reading; students- or teachers-moderated issue discussion; peer evaluation and review; collaborative construction of knowledge bases; and projects on-line presentation. Quantitative as well as qualitative dat a and analysis regarding the different modes is presen...