IT organizations today are tasked with a variety of development projects ranging from new Web-based applications to business-to-business integration (B2Bi). In all of these projects, integration of existing systems plays an important role. Traditional enterprise application integration (EAI) has delivered on connecting applications together, but it has failed in other major requirements for IT development, namely: cost (development and maintenance), time to market, flexibility, extensibility, reusability, and return on investment (ROI).