eric: if I stand on my origin, how am I supposed to make any sign on your fork, or yours on mine? chat 
Authors can only edit their own pages.
You might fork one of my pages and improve it greatly in your own copy. When I become aware of your improvements I can accept your gift by forking your page back to my site.
If, however, you have taken the topic in a direction that doesn't suit me, I can decline your edits.
This is definitely a very different sort of collaboration than what people know from experience with Wikipedia or similar wikis. In particular, we can partially agree and partially disagree. Each of us maintains our own view of the world.
It solves another question: What About Abuse?
It wildly reduces complexity for a distributed database of pages. That reduces the operational load for operators of wikis. It also improves the developers chance of maintaining the code with only the recreational time of a few volunteer programmers. See also Why "wiki" especially the reference to Scale is a Trap—we're building to outlast ourselves by building small and sustainably.
If our collaboration grows into something compelling, fedwiki has affordances to follow more closely.
Mud Wrestling fedwiki.grin.hu ward.mud.asia.wiki.org mud.dbbs.co
ROSTER Mud Wrestling TWINS 2 CONVERSATION
For another example, I really like how Ward and Thompson have worked together through wiki.
Ward described his wiki conversation with Thompson as an especially informative experience. I have constructed an experiment using the Activity Plugin and the Roster Plugin to capture an index into their collaboration.