I actually see SOA as a tool for achieving EA. EA partially involves rationalizing the entire set of business functionality for an enterprise into the smallest amount of code and components without sacrificing too much. You strive to optimize the app portfolio, determine what is common/reusable and then strive to eliminate the redundancy.

Achieving the goal of common services in a real-time enterprise simply becomes incredibly easier with SOA and the technological advances of the past decade. There are standards-based ways to define contracts, security and numerous other concerns. These standards are vendor-neutral. Architects begin to think in terms of applications and service inventory. Composite applications can be assembled from the service inventory a lot faster than doing it the old way (it’s still hard work, though).

I’ve been working on an SOA strategy at my present company for about three years now. While it’s not perfect yet and probably will never be, I see us achieving a lot of success with it.