Disclosure: I am an employee of Stellent, Inc. We develop and market a commercial CMS package.
WebDAV has a lot of momentum, from our perspective, not only from a product standpoint but also from a customer requirement standpoint. WebDAV is not just a web-folder sharing methodology in which content is physically located in a folder structure much like you would see within a traditional file server. To say it differently, its not just enabling access via the web to folders within a file server. WebDAV as a communications medium between a centralized respository, using policy/role based access to content objects, and an end-user is not only possible but available in a number of commercial products today. This includes the ability to present, based on user or groups or roles or whatever security model they use, a folder structure and views within each folder that is determined by that users permissions. In the end, its only a virtual representation of the traditional file hierarchy metaphor with the single authoritative source object being managed. As for the complexity of building such a system and how best to go about it, I will not approach that subject for obvious reasons :) -- http://cms-list.org/ trim your replies for good karma.
