Nodes exist in a network and, in this context, can share information (status updates, social graph additions, etc. ) with other nodes. But these nodes would control what information they share the Facebook model.
Can a user belong to as many nodes as he or she wants? Can a user run as many nodes as he or she wants?
Is a node a real, physical thing or just a co-opted version of the networking term?
What would it mean for an end user to belong to two nodes versus ten nodes?
You know, the same kind of friend that uploads photos of you drunk.