I get the idea of having a panel discussion like those taking place in professional conferences. But how about adding co-authorship across the board?
Say I am contributing/reacting to a post about career change. While composing my reply I realize my buddy Chris has a complimentary story. It would be nice to request his contribution right on Cake. The idea here is the old adage: the total is more than the sum of the parts. Co-authorship could be really powerful. It could make it much harder to post troll or trash content, and by making the co-authorship a feature visible to potential readers, it would indicate the relative value of the post.
The implementation example that comes to mind is having Google docs embedded into Cake, with realtime collaboration.
Just a tought.