Ross has a fascinating post on Participation Power Laws - along with an interesting diagram. What Ross is getting at is what so many companies miss in creating blogs. It isn't about the posts and publishing as much as it is about engagement with the community.
When users participate in high enagement activities, connecting with one another, a different kind of value is being created. But my core point isn't just the difference between these forms of group intelligence -- but actually how the co-exist in the best communities.