I won't be surprised if all the vendor marketing materials touting "SOA-enabled" technologies is soon be replaced with pamphlets and whitepapers touting "WOA" capabilities.

WOA stands for web-oriented architecture, and though it's not a new concept (obviously -- how old is the Internet anyway?), it's gaining attention from industry thought-leaders, thanks in part to SOA's pending dive into the pit of disillusionment and in part to the growth of SaaS providers and Web 2.0 technologies.

The main question seems to be how WOA relates to SOA. Some say it's the next evolutionary step for SOA, some say it's just another name for extending SOA outside the firewall, and a few seem to characterize it as a competing approach.

It's probably not unfair to say it's a bit of all those things.

From what I can tell, this debate is still in its early stage and very much a discussion of possibilities, rather than recommendations. But, there's no doubt in my mind you'll be hearing more about it, so I put together this introductory de-briefing on WOA:

Why WOA, why now? Dion Hinchcliffe, editor-in-chief of the Web 2.0 Journal and AjaxWorld Magazine and founder and CTO for the consulting firm Hinchcliffe & Company, started this discussion churning with a lengthy February post titled, "What Is WOA? It's The Future of Service-Oriented Architecture (SOA)." As you can probably guess from the title, he sees WOA as an extension of SOA, with some key technology differences.

In fact, he calls the Web the "largest SOA presently in existence." If you can read only one thing about WOA, read this article.

Integration is a key selling point of the WOA. Initially, SOA promised better, easier integration. It hasn't really delivered, according to Hinchcliffe, but where SOA has faltered, the Web has succeeded:

"...the fascinating story is that there is a place today where the deep integration of our systems and information on a large scale has largely been solved and is a foregone conclusion in most cases. And that place is at the leading-edge of the World-Wide Web, sometimes referred to as Web 2.0."

REST, Not SOAP. There are a lot of similarities between SOA and WOA. But there are differences, too. Tony Bear of OnStrategies -- in a post aptly titled "IT Forecast Is Partly Cloudly (I)" -- explained how endpoints look very different in SOA as compared to a web-oriented architecture:

"...while SOA has a finite set of well-defined endpoints, WOA is just the opposite: they consist of resources with assigned endpoints that can be located by search engines rather than UDDI registries; are accessed using RESTful approaches via HTTP rather than SOAP; and use service contracts that are implicit, rather than formally spelled out in a WSDL web service description."

Hinchcliffe's February post outlined the basic tenets of WOA as including making information available as a resource on the network, "accessed and manipulated via the protocol specified in the URI, typically HTTP." He also explains why WOA uses REST, as opposed to more SOA-associated technologies, such as SOAP, WSDL, and XSD.

You might also want to read this more recent ZD Net blog post, in which Hinchcliffe elaborates on REST's role in WOA and how WOA would look implemented within the enterprise.

WOA's Still SOA. While WOA differs from SOA, it doesn't throw out the key tenets of SOA, according to Hinchcliffe, who adds a WOA "embodies Thomas Erl's essential Principles of SOA, though in often unexpected ways."

As I mentioned, this conversation isn't new, but it's still very much developing in terms of how SOA and WOA will interact. In some ways, it looks like just another battle ground for the whole internal versus external IT discussion we've had since the Web found its way into business.

But as SOA expert and new StrikeIron CEO David Linthicum pointed out, SOA was never really supposed to be about internal IT systems:

"As I've been stating for the last 5 years, SOA should extend out of the firewall to the Internet, if you're to provide real value to your enterprise. However, this was not universally accepted by the rank-and-file SOA guys ... WOA is really SOA using 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."

WOA May Save SOA. Hinchcliffe and others say WOA may be the missing key to pushing the principles of SOA into wider enterprise adoption:

"Traditional SOA is facing a crises of identity at this point, particularly given fairly lackluster results for most, and WOA may just be the prescription we need to make SOA deliver the robust outcomes that we were formerly expecting of it."

In "WOA may soon eclipse SOA as most impactful business transformation agent," Dana Gardner, president and principal analyst at Interarbor Solutions, argued WOA actually goes a long way to help the ROI/business use case for SOA:

"I'm seeing a lot of good productivity being created from both legacy modernization and new Web development-and-deployment efficiencies -- and they are by no means mutually exclusive. Indeed, data integration advances and Web oriented architecture together may be the real SOA adoption path."

Gardner also wrote about how the WOA/SOA dynamic might play out in the vendor space. I particularly liked his point about Microsoft, which he says "already understands the power of WOA plus SOA." If true, that would certainly explain a lot about why Microsoft's SOA strategy has seemed pretty fuzzy thus far.

That's WOA, in brief. At this point, I think Linthicum offered the best advice on what to do with all this WOA/SOA discussion:

"So, relax. WOA is a new term offering a new way to think about new things, in the context of old things."