As I've been stating for the past five years: if you want to provide real value to your enterprise, SOA should extend out of the firewall and into the Internet. However, this was not universally accepted by the rank-and-file SOA guys. Generally speaking, most viewed SOA as something that occurred exclusively within the firewall, and extending the reach of their SOA to Internet-based resources was taboo.

Thus, the notion of WOA, or Web-Oriented Architecture, is really SOA that uses Web-based resources including services, applications, directories, tools, etc., and the general acceptance that it's okay to place business processes outside of the firewall. Not sure if anyone is selling this as a replacement to SOA, or traditional enterprise architecture, but it's really an approach to architecture where there is a core acceptance that Web-based resources may provide the most speed to delivery, the largest number of resources, and a minimum amount of cost.

The general notion is that the Web provides another location for core business processes using outsourced infrastructure and reusable business processes that are accessible on-demand. These Web-born systems/architectures provide better development speed, access to pre-built resources, and much more value when compared to traditional enterprise approaches. These are the reasons SOA proves itself on the platform of the Web more so than within the enterprise these days…it's just faster, easier, and provides more initial ROI.

Keep in mind that enterprise SOA projects are still progressing. However, the use of Web-born resources, such as on-demand Web services, SaaS, and on-demand tools such as Google's new App Engine, is creating more of a grass-roots movement toward SOA/WOA. This movement is shifting from the developers to the architects, not from the architects to the developers. The former is much faster.

The same pattern was seen with the rise of SaaS. Salesforce.com did not sell to IT. IT would block any attempt to leverage remotely hosted applications. Instead they sold to those who had the pain and needed a quick and easy solution, and SaaS filled that need nicely.

IT only adopted SaaS after there were so many SaaS users within their enterprise that they wanted to subsume and control the use of SaaS. I've personally seen IT leaders push back hard on SaaS, then change their tune once they've seen the value, or are forced to see it. There is always a not-invented-here issue with this technology, and clearly you can no longer hug your server. Those who were in denial are now coming around.

The adoption of Web-born SOA, or WOA, is finding a similar adoption pattern. Composite applications will be and are being built within emerging on-demand tools such as Google App Engine. Those applications will need information, services, and APIs, also delivered on-demand over the Web. Moreover, enterprises will seek to externalize existing enterprise data to WOA as well and thus user management and security will remain a core issue. Indeed, we could see many enterprises with more business processes running outside of the firewall than within, in just a few years.

Once that trend is clear, as it's becoming today, we'll find that more sophisticated core architectural technology will become more mature on the Web as well. This includes SOA governance on-demand, and service directories inclusive of visual and non-visual services available for mashing up into solutions. In essence, process-by-process, application-by-application, and service-by-service, we're re-hosting core business processes and services on the Web.

While this was science fiction just a few years ago, it's happening today, guys.

• SOA and the Rise of WOA
• WOA for the Enterprise