An entry on the Zapthink website discusses the relationship between outsourcing and service oriented architecture (SOA).
The combination of the SOA and outsourcing trends reflects the maturation of the IT industry. Before the industrial age, companies built products and tools on a one-off, customized basis, but with the emergence of powered machinery, improved technologies, and new methodologies, companies were now able to mass produce all manner of goods for the first time. The convergence of the outsourcing and SOA movements illustrate that IT is becoming industrialized as well. In many ways, SOA represents the technology required to “mass produce” highly reusable IT components. Outsourcing reflects the increased desire of companies to stop custom producing their own IT components. In this regard, SOA and outsourcing really are two aspects of the same macroeconomic trend towards the industrialization of IT. [ZapThink :: Intelligence, Research, Analysis, and Insight on XML, Web Services and Service-Oriented Architectures]