Paradigms Restrained: Implications of New and Emerging Technologies for Learning and Cognition 
Mary B. Shoffner, Marshall Jones, and Stephen W. Harmon survey a broad range of educational technologies, including those mechanical and those philosophical, and conclude that it is the underlying pedagogical philosophy, and not the delivery mechanism, that most affects what students learn.
Shoffner, Mary B., Marshall Jones and Stephen W. Harmon. Journal of Electronic Publishing (2001). Articles>Education>Instructional Design>Online