I don't understand the point here I guess. Facebook is clearly a service to people. People need validation and they can come here to get it quickly and easily - they also come here to stay in contact with friends and family. The work being provided is you using their service - so its not unpaid feudal system work, it is you coming for a personal benefit that in turn produces profitable output for facebook. This is just an odd analogy in my opinion, one a bit too simplistic.