The Next Generation Service Overlay Network (NGSON) is a standard activity launched by IEEE Communications Society in March 2008 to define a framework of Internet Protocol (IP)-based service overlay networks and specify context-aware, dynamically adaptive, and self-organizing networking capabilities, including advanced routing and forwarding schemes that are independent of underlying transport networks. Service interaction research, specifically how to harness service interactions to facilitate service integration and bundling in such a service overlay network, has been the focus of this standard activity. This paper reports the still evolving ideas of IEEE NGSON architecture and describes the new challenges in service interaction research in such a framework.