The key relationship in a service-oriented ecosystem is between a consumer and service. However, there may be more roles beside Consumer and Service, e.g., Service Provider, Service Owner. From a business perspective, there are Consumers, Partners, Providers and Suppliers in the SO ecosystem.
The more Business penetrates into Technology and the more Technology acts as a Business, the more business relationships affect Business Services and their interrelationships. In SO ecosystem, everyone exists in two roles simultaneously - everyone is a consumer and a service. As a service, everyone wants to win as many consumers as it can serve; as a consumer, everyone wants to be served in the best possible way. At the same time, everyone is fully independent from others (there is no "developers" who can tune consuming and providing SW to work in this or that way).
To deliver the best service and to receive the best service being independent, participants of the SO ecosystem have no other choice that to apply the rules of relationship as the following:
A Service of my Server, is not my Service
A Consumer of my Consumer, is not my Consumer
A Partner of my Partner, is not my Partner
A Supplier of my Supplier, is not my Supplier
If one ignores these rules, sooner than later it will lose its serviceability.