sentences: Modern charging systems use user, network, and service related information when performing online charging. Compared, however, to the overall information available and used in network management processes as a whole, charging systems only use a limited subset. This work is motivated by the challenge to identify which information is used, and how it is used in online charging related processes, and also to explore whether it could be utilized “better” or “smarter” to improve future online charging systems functionality. We do not attempt to predict which information will be utilized in such systems and for what purpose, but instead we summarize open issues in view of the emerging trend of exploiting the user, network and service related information in service provisioning. We focus on the latest 3GPP standards and review relevant research papers, and propose three key aspects of online charging, with respect to information utilization: a) signaling aspect, b) inter-domain aspect, and c) serviceand component-based aspect. We present a state of the art review by grouping the works found in the literature based on the aspects they are associated with, and compare them based on proposed comparison criteria. The discussion presented at the end of the paper indicates three common open issues, namely: 1) lack of common charging information specification and structure, 2) lack of mechanisms for information sharing between stakeholders in the service delivery process, and 3) lack of a common framework for sharing information while protecting user privacy. Copyright c © 2012 John Wiley & Sons, Ltd.