In this approach the instructor/course treats the class community as a homogeneous element -- trying to move it in lock step from Point A to Point B. Community-based assignments, then tend to be discussion prompts in which homogeneous community members provide an answer to a homogeneous question set based on a collection of homogeneous information. After each member of the homogeneous class community has posted their fairly homogeneous response to this homogeneous question based on a homogeneous set of information, individual students are then asked to reply to the homogeneous responses. It is at this point, I believe, that the community connections are supposed to occur. In reality, by this time, all posts are pretty much the same so students just pick a couple and write their homogeneous replies without needing to give much thought given to the original posts. Occasionally, some student who either doesn't understand the instructions or doesn't understand that they are supposed to be acting homogeneously, will fly off the rails and disrupt the whole enterprise. The homogeneous structure of the course is generally so strong, however, that this type of insensitive behavior is quashed rather effectively.
I contrast this with the Storybook Project that my friend Laura Gibbs employs in her Mythology and Folklore online course. In this course design models, students are treated as heterogeneous community members who are allowed to select and write heterogeneous stories/posts based on heterogeneous information sets tied together by a common set of ideas. As a result of the individualization of the information and the topics, students write creatively and passionately. Other students, when asked to comment on the storybooks created by other students, often do so with equal interest and passion, which leads to legitimate connections and a vibrant community.
In case I haven't made the contrast clear, ere is a simple visual of the two models.