[For anybody who is doing SOA or Web 2.0 development I strongly encourage them to take a look at this web site. Lots of useful information and SOA, Web 2.0 and Mashups - and an amazing demo to show that it is all real. Thanks to Benoit Pirenne for this pointer. Some excerpts from the Adobe web site -- BSA]
http://www.adobe.com/devnet/livecycle/articles/soa_gis.html
Very good article on marrying GIS with SOA; see the demo of the bike
race at http://www.adobetourtracker.com/max/Simulator.html
The emergence of the Internet in the mid 1990s as a platform for data distribution and the advent of structured information have revolutionized our ability to deliver rich information to any corner of the world on demand. The move towards Service Oriented Architecture (SOA) infrastructure has been essential to the development of modern distributed systems. Service Oriented Architecture is an architectural paradigm and discipline used to build infrastructures that enable those with needs (consumers) and those with capabilities (providers) to interact via services though they are from disparate domains of ownership.
The evolution of software systems over the last two decades has resulted in a migration to a common set of design patterns that are often referred to as Web 2.0, or the maturing of the Internet. This migration is being enabled and accelerated by the move to Service Oriented Architecture, also known as SOA. This evolution path of software systems architecture is documented in
Many developers building geospatial applications today embrace some of the core patterns of Web 2.0 such as the Mashup, Software as a Service, and Rich Internet Application patterns. (These patterns are documented in the O'Reilly book Web 2.0 Architecture Patterns, J. Governor, D. Hinchcliffe, D. Nickull – ISBN 0596514433.) All of these patterns rely on a fundamental change in the software model used to architect multi-tiered systems. This core change is the migration to SOA as an evolution of the old Client-Server model. The old Client-Server model was the cornerstone of the first iteration of the Internet (roughly 1994-2000). It was largely implemented by web servers and browsers with idempotent request-response message exchange patterns. In the subsequent evolution of the Internet (2002-2007), the model has changed and now SOA has become the de facto standard for application architects and developers. As shown in Figure 1-2, the "server" component of the Client-Server model has been replaced with a services tier which enables capabilities to be consumed via the Internet, using a standardized set of protocols and technologies, by client applications for the benefit of the end user.