I'm late in joining this discussion so my comments may have already been hashed over by others. It looks interesting., I think the guidelines from S.O.S. make a lot of sense. Some other models that might be useful in addition to a BBS are: Chat, Persistent Chat, Document Library, and social bookmarking.

Chats:

We already have a basic chat model with Gably but it would be good if these chats could become long term objects that had the ability to evolve over their life. It is sort of a cross between a real-time chat and a thread.

Doc Libraries:

A document library could be simply a set of useful indices's to other material or could be used to a) Storing long writups b) Cooperatively developing long writeups.

Social Bookmarking: A cross between Google Bookmarks and Diggs. This could be implemented as part of an index and link oriented doc library too, where the references (links) could contain metadata like ratings, commentaries, links to related materials, etc.