First, some background: If you really believe the XML storyline, XML is the Swiss Army knife of content formats, enabling you to write contet once and use it many times. No, wait, it's the most ubiquitous application language for new web services and desktop publishing applications. In fact, XML has suddenly made the move into being both the content format AND the applicatioin format in MS Office 2007 and Adobe Creative Suite.

On the content side, you can think about reusing content in multiple ways. Here are a few suggestions that are common:

• Including the content of one XML file in another, as with DITA maps*
• Making a pointer to an XML file, so that another application or process will grab the content and pull it into an output process, as in DITA conrefs
• Combining XML resources from a variety of different applications into a single display, as in a mashup of Twitter, RSS, and Flickr
• Including XML snippets in a larger XML file, as with Adobe FrameMaker and InDesign
• Saving content from one XML-enabled application as XML to use in another XML application

You can add your own ideas.

* More about DITA later in the blog series.

On the application side, it gets interesting very quickly. If MS Ofice files and Adobe Creative Suite files are all written in some form of XML, which means that:

• Applications in the same suite can be written to programmatically enable them to interact seamlessly (i.e., work with Excel from withn Word, work with Photoshop and Illustrator from within InDesign).
• Applications from different suites can exchange files with more sophisticated "save as" options if the application owners are cooperating or by transforming from one form of application XML to another with XSLT, if there isn't a "save as" function.

Can we play with these capabilities? Can we move content around in different applications suites and reuse it, transform it into some different form of XML, and leverage both content XML and application XML for our benefit?

So this leads to the second issue: We'll need a plan for this journey, starting with determining the best application and content type for each XML feature we want to demonstrate. Since we want to "eat our own dog food," we'll have to use XML content and XML-enabled applications. The outline for our content will be a ditamap created in an open-source XML editor. We'll post sample files that you can download as we develop each type of XML content and create re-use in each application. Grab your backpack and your flashlight and come along as we explore XML in MS Word, Adobe InDesign and FrameMaker, open-source DITA, and XSLT.