As we have been gaining more experiences in services provision, online services are becoming increasingly complex. They have moved from simple service provision and invocation to very sophisticated service interaction and cooperation. As presented in this paper, service cooperation will be a promising computation model to achieve overall goals beyond individual capabilities. Based on the supreme wide spread of Service-oriented Development (SODA), the Process-oriented Platform (POP), with favourable flexibility derived from late binding, will be the optimum approach to this end. The PI production developed by us is such a system implementation, which architecture, components, and functionalities are also introduced in detail. We believe that the service cooperation paradigm is a hopeful solution to future service evolution, and the PI system will be an instructive explorer to reach this new horizon.