Instructional design in learning communities has some different features than traditional courses. In learning community instructional design there are different levels of participating and varying opportunities for learning. A nice example of this model is provided by WorkLiteracy that is hosting a Free Web2.0 seminar.
In this program they have identified three levels of participation--spectator, joiner/collector and creator and have prepared learning materials for each group. As you might guess from the names, each of these represents more depth of participation. The three "learning types" are based on participation types that have been identified by Forrester in their book called Groundswell based on data they have analyzed in terms of their own analysis of participation on the web. These different types are somewhat similar to my own "theoretical" categories of possible participants in learning communities.
An important aspect of the WorkLiteracy example is that the instructional design provides explicit ways to participate that require more or less interest and investment by the learner. Importantly, if this work was designed to persist over time, the design would include ways to transition from being a spectator to being a joiner/collector, etc. (We still know little about this process, but theoretically this would occur.)
Another aspect about the WorkLiteracy course is that there are numerous tools to use to engage with the course and bridge across other activities so participants are immediately offered the opportunity upload images or videos, to join a forum, to invite other to participate or to create an interest group within the community. Each of these activities may appeal to various participants. Even within the general categories of learners there are ways to make various contributions.
Overall, this is a very nice model.