There are different ways of defining what constitutes the domain of a service inventory. It can be based on anything from zones of authority, to geography, or large-scale legacy environments. The "healthiest" approach is to align domain inventory boundaries with actual business domains. This helps sync the physical macro view of a service-oriented technology enterprise with logical areas or lines of business that may exist, which can greatly facilitate long-term business-technology alignment.
There are also different and creative ways of applying this pattern. For example, domain service inventories can be used to phase SOA adoption into an enterprise over time. There may also be the opportunity to expand or otherwise augment individual domains after their initial definition, allowing for a more evolutionary proliferation of services.
Either way, it is critical to understand the option presented to you by this pattern. Because it makes SOA accessible and attainable to just about any organization, it has become the most popular means of successfully realizing the business value offered by service-oriented computing today.
The SOA Pattern of the Week series is comprised of original content and insights provided to you courtesy of the authors and contributors of the SOAPatterns.org community site and the book "SOA Design Patterns" (Erl et al., ISBN: 0136135161, Prentice Hall, 2009), the latest title in the "Prentice Hall Service-Oriented Computing Series from Thomas Erl" (www.soabooks.com).