Information intermediation is the foundation stone of some of the most successful Internet companies, and is perhaps second only to the Internet Infrastructure companies. On the heels of information integration and interoperability, this text on information brokering discusses the next step in information interoperability and integration. The emerging Internet economy based on burgeoning B2B and B2C trading may soon demand semantics-based information intermediation for its feasibility and success. B2B ventures are involved in the "rationalization" of new vertical markets and construction of domain specific product catalogs. This book provides approaches for re-use of existing vocabularies and domain ontologies as a basis for this rationalization and provides a framework based on inter-ontology interoperation. Infrastructural trade-offs that identify optimizations in performance and scalability of web sites may soon give way to information based trade-offs as alternate rationalization schemes come into play and the necessity of interoperating across these schemes is realized.