Building smart meeting rooms requires the support of a computing system architecture. In this paper, we describe the Context Broker Architecture (CoBrA), a broker-centric agent architecture for pervasive context-aware systems. CoBrA exploits the Web Ontology Language OWL for supporting knowledge sharing and data fusion, uses logic inferences for resolving and detecting inconsistent context knowledge, and provides users with a policy language to control their private information. Central to CoBrA is an intelligent broker agent that maintains a share model of context for all agents, services, and devices in the space, and protects users’ privacy by enforcing the policy rules that they have defined. We also describe the use of CoBrA ontologies, context reasoning mechanisms, and privacy protection in a smart meeting room system called EasyMeeting.