What is the value proposition of an open standard?
XML is fairly pervasive, so we rarely ask this question of XML anymore, but once upon a time the question came up a lot as business managers tried to figure out why the technical people were insisting on spending money to move to XML. And the truth is that the impact is difficult to measure precisely, so open standards are sometimes a bit of an uphill battle. Nevertheless, the software engineering benefits are tangible and increase in magnitude over time.
One benefit is, of course, the human resource factor. Given a schema or DTD for a pile of pointy brackets, human beings can learn a lot about your document format quickly, which means they can become proficient more quickly and be more efficient overall at moving information into and out of the document.
This has an impact on the development of software systems. The software engineering benefits of increased interoperability/looser coupling of system modules have a significant positive effect on the time and cost efficiency of software development. Really, it's the same benefits as a service oriented architecture, which is why SOA and XML documents are such a good match.
But XML standardization has a deeper impact as it also places a value on the document format. In other words, the document format becomes a product in and of itself. A software system based on an XML document format is more valuable than one that is not because it is easier for enterprises to migrate to or from the document format. The benefit to a vendor of enterprises being able to migrate to the vendor's format is immediately obvious, but the ability of the enterprise to migrate from the vendor's format is also surprisingly valuable to the vendor. This is true not just for the obvious reason that being trapped in a document format is inherently costly to an enterprise. So, the enterprise can more readily adopt a vendor's solution when it does not imply vendor lock-in, but frankly it is the capability to more easily migrate away from the vendor's solution that becomes a selling point. A vendor can say, "We know you have a choice, so we're going to be responsive to your needs and deliver quality software so you keep choosing us."
It is with all these benefits in mind that we moved the predecessor of Workplace Forms to an XML syntax called XFDL. The XFDL language is an XML vocabulary that simplifies the design, development and deployment of high precision, secure forms applications that provide a rich user experience.
Of course, the first thing we did with our new XML syntax was to report it to the W3C in a document which became a W3C Note. The purpose of a W3C Note is to bring to the attention of the W3C something that contains aspects worth of consideration for standardization. The W3C does not and never will standardize a vendor's submission. But it does take note of its own notes! A positively reviewed note is likely to result in some movement in the standardization world. In the case of XFDL, that movement has occurred all over the place, including the likes of XPath, XML Schema, XML Signatures and Canonicalization, and XForms.
Of course, XFDL now incorporates XForms to express all aspects of XFDL that it can. And like a good standard ought to do, XForms itself incorporates other W3C technologies where appropriate, like XPath and XML Schema. But XForms depends on a host language to deliver the actual user experience, and there are aspects of a precision presentation and rich user experience that properly belong at the host language level. And XFDL even encodes these bits with the most pervasive standard of all -- XML.