--- a/whitepaper.txt	Tue Feb 02 16:39:08 2010 -0500
+++ b/whitepaper.txt	Fri Mar 26 14:03:44 2010 -0700
@@ -131,4 +131,16 @@
   'messages': [ list, of, children ],
   'next':
   'previous':
-  'parent': } 
\ No newline at end of file
+  'parent': } 
+
+
+Discussions -> Collaborative Documents
+--------------------------------------
+
+discussions presents a strict hierachal document that can only append
+leaf nodes.  Collaborative documents (e.g. a wiki) may also be
+hierachal, but additional functionality is implied:
+
+ * the ability to edit nodes
+ * the ability to merge nodes
+ * the keeping of history (including all implied functionality of an VCS)