With the diversity of accessing devices, WWW content needs to be designed for both PC and non-PC devices, so that it can be appropriately navigated and rendered by each type of devices. Instead of developing a separate version of each site for each family of devices, people are beginning to try to separate its presentation from the basic content and to apply the appropriate presentation to the content for each target browser device. XSLT has seemed to be the answer, but people are getting to realize that XSLT alone would not be enough to meet all the requirements. It can not produce a document flow, or a dialog, from an single XML content.
In the Note submitted to the W3C, NEC introduces the concept of navigation which specifies a scenario to expose the data to the user and proposes XDNL, or XML Document Navigation Language which describes the navigation. XDNL can produce a document flow, or a dialog from an XML document. Together with XSLT, it can produce HTML, WML, VoiceXML or whatever.
XDNL in itself may be still immature but we believe it can be a good starting point to address the issue.