Collaboration promoted and supported by instructional technology has the potential to lead learners to deeper understanding and knowledge building. There have been optimistic views that any web-based interaction can be educationally valuable. However, online learning environments do not, as such, guarantee that learners will achieve genuine collaboration. It seems that there are several difficulties facing those who wish to employ online learning environments as a medium for productive learner interaction. The particular aim of this exploration of interaction and learning in computer-supported collaborative learning environments was to study the interplay between learners and consider the ways in which they built and maintained common ground so as to enable themselves to work and learn together. Another aim was to look at the effects of scripting interaction with a view to finding out how scripting can enhance or hamper collaboration. The work opens up a perspective on online communication as a distinctive type of human interchange whose special features challenge designers, researchers, teachers and learners involved in computer-supported collaborative learning.