The term 'Social Machine' (SM) has been commonly used as a synonym for what is known as the programmable web or web 3.0, where several web-based systems make their APIs publicly available and establish connections with each other under several and complex restrictions. Some definitions of a Social Machine have already been provided and they basically support the notion of relationships between distributed entities. The type of relationship molds which services would be provided or required by each machine, and under which constraints. In order to deal with the complexity of this emerging web,...