Hi,
Just discovered and tried fopnu. Seems nice.
I was looking for a way to sync a folder through wan/lan by p2p for various collaboratives users.
The idea is something like cloud synchronizing, always adding to all users' folder the new files no care where there are coming from as long as they are from the group of collaborators.  
The purpose is to create a kind of collaborative library.
The maintaining could be achieved by a unique "master" controled folder, so removing a file from it (a duplicate for example) would remove it from all the others.
Hope some people will find this interesting.