Challenges: Some Ugly Truths
The challenges of building—and living with—an XML workflow are clear enough. The return on investment is a long-term proposition.
Regardless of the benefits XML may provide, the starting reality is that it represents a very different way of doing things than the one we are familiar with. The Word Processing and Desktop Publishing paradigm, based on the promise of onscreen, WYSIWYG layout, is so dominant as to be practically inescapable. It has proven really hard to get from here to there, no matter how attractive XML might be on paper.
A considerable amount of organizational effort and labour must be expended up front in order to realize the benefits. This is why XML is often referred to as an “investment”: you sink a bunch of time and money up front, and realize the benefits—greater flexibility, multiple output options, searching and indexing, and general futureproofing—later, over the long haul. It is not a short-term return proposition.
And, of course, the returns you are able to realize from your XML investment are commensurate with what you put in up front: fine-grained, semantically rich tagging is going to give you more potential for searchability and recombination than a looser, more general-purpose approach, but it sure costs more. For instance, the Text Encoding Initiative (TEI) is the grand example of pouring enormous amounts of energy into the up-front tagging, with a very open-ended set of possibilities down the line. TEI helpfully defines a level to which most of us do not have to aspire.[5]
But understanding this on a theoretical level is only part of the challenge. There are many practical issues that must be addressed. Software and labour are two of the most critical. How do you get the content into XML in the first place? Unfortunately, despite two decades of people doing SGML and XML, this remains an ugly question.
It is the consistency of the WebKit document model across all WebKit browsers that makes for an interoperable Open Web future. I would not however discount the importance of Firefox and Opera embracing the WebKit document model (HTML5, CSS4, SVG/Canvas, JavaScript, DOM2). That's our guarantee that the future of the Open Web will actually be open.
Tom goes on to suggest that instead of "AJAX", developers would be better off thinking in terms of "ACHJAX": Asynchronous CSS4 - HTML5 - JavaScript and XML ..... with the focus on getting as much done in CSS4 as possible.