The group does assign a reporter to

The group does assign a reporter to compile the final report so there is a role assignment aspect. Forsyth (1999) argues that the sense of belonging in a group is essential for team formation, and Kirschner et al. (2004) argue that functional roles can provide group cohesion, a sense of responsibility and interaction all leading to social affordance.
The group task (production of the collective report) is not assessed and the activity remains optional. However the group's task is linked to individual assessment task and students are encouraged to make reference to peer contributions in their individual assessment. By completing this task, students can combine their efforts to cover a bigger portion of the work than they could achieve on their own and in turn this may help their completion of the course assignment (leading to positive interdependence and promotive interaction).
Conclusions
The use of content analysis in this study has been shown to be beneficial as a way of evaluating the educational effectiveness of an online discussion. The content analysis of the online seminar provided us with an understanding of what issues students were talking about, how they were using the course materials to further their learning and the extent to which their activities were collaborative. This also provided evidence of learning processes occurring in the online seminars in this graduate course. We were able to label messages that contribute to group task by providing knowledge, references, examples, questions and explanations.
In addition to these analyses we used Kirschner et al (2004) framework for designing electronic environments focusing on educational and social affordance of CSCL systems and critically considered the nature of task design to separate the factors that may have contributed to the success of the online seminar.