This paper describes the emerging need of feature interaction managers in Next Generation Networks that are based on a convergent IP architecture to support voice, data, and multimedia services. Though this need has been addressed by the telecom industry with various architectural components under different names such as Service Capability Interaction Manager (SCIM) in the 3GPP (3rd Generation Partnership Project) IP Multimedia Subsystem (IMS), the consensus of the industry is to call such a network function Service Brokering and the network component fulfilling this function Service Broker. This paper reports the current industrial status in architecting the Service Broker, discusses the limits of the Service Brokering functions defined in 3GPP, and points out open issues for further research.