The rapid deployment and expansion of the Internet has created both an opportunity as well as a challenge in terms of service delivery. The opportunity comes from the variety and global scale of value added applications that can be supported for users. The challenge comes from the difficulties of developing and deploying software to support these applications and users. Service Oriented Architecture (SOA) and Service Delivery Platform (SDP) were introduced to help with these issues, but lacked support for service delivery and QoS across different domains. Service Overlay Networks (SON) were then introduced as an intermediate layer to support the creation of value added serviced over heterogenous networks. Over time however, SON has run into intrinsic limitations in terms of handling the increasingly dynamic nature of users, services and networks which characterize todays global network. The IEEE P1903 Working Group proposed Next Generation Service Overlay Network (NGSON) to address some of these limitations. NGSON supports service delivery over various kinds of IP-based networks, while leaving QoS support to the underlying network. NGSON aims to support context-aware and adaptive features within the service control and delivery functions of SON, with the ultimate goal of improving the user's quality of experience (QoE). In their article, the authors explain the basic concepts behind NGSON, including a review of recent standardization activities. Technical challenges and roadmap items are also discussed. Interested readers can continue on to more detailed articles in the same issue if interested.