Most of the seniors were doing their pre-student teaching observation hours. The remaining students in the class were minors in English Education. All subscribed to the class list, COMP-L, serviced by a listproc program. For full credit students needed to send four messages per week. I described the list as a site for discussing the readings and topics raised in class, though I did not limit it to only that.
Successful lists encourage, even require, the adoption of definable roles by the participants.