I recently discovered some notes that I had made back in November 2004 from a TIBCO webinar “Enabling Real-time Business with a Service-Oriented and Event-Driven Architecture”. Randy Heffner from Forrester spoke at that webinar, and I remember that it was his words that made me realize what an impact that SOA was going to have, and how strategic SOA requires a focus on enterprise architecture, particularly the application architecture and technical architecture layers, so that business and IT metrics can be tied back to defined services.
Although it seems obvious now, that webinar really crystallized the idea of services as being process steps to be orchestrated, and how this allowed you to focus on an end-to-end process across all stakeholders, not just what happens inside your organization: the Holy Grail of BPM, as it were. EA often does not include business architecture, but services force it to consider the business process architecture and business strategy/organization.