The brain of WinFS is what's called the data model. The term conceals a mechanism that uniformly administers and structures digital elements. Microsoft talks about "items" in this context. The word is a good choice, since items add a range of further descriptive arguments to each file. These parameters do not occur in a file's header, though, but are administered solely by WinFS. No changes then as far as the physical data structure goes, which is still looked after by NTFS. Under this scheme, not only files, but contacts, favorites and mails as well are registered as items.
From the user's standpoint, items degrade the files' physical storage location to the point of insignificance. Instead, Windows organizes the data according to content in virtual folders. In searching for these data, user-based criteria such as "All vacation pics of the last two years" replace details such as file format, author and storage location.
Microsoft has gone with a variable item model for WinFS. Developers can define further items using XML metadata and determine relationships between items. This enables, say, all documents by a certain author to be automatically displayed together with address data and contextually related images.
The view options in the file explorer and the commands linked to certain file types are variable in design, too. Developers can stipulate which tasks in the context menu are available for which items and which thumbnails are selected, for example. Hence, the file explorer in Longhorn can take on a whole new range of tasks. It will mean, for instance, that developers will additionally be able to automatically display or execute commands linked to items located by a specific search. If the user makes a search of mails, for example, the Explorer can be used to get Outlook to prepare and send a standard response mail - all at the click of a mouse.
It seems equally probable that a link will run from Microsoft's envisaged Rights Management to the Next Generation Secure Computer Base (NGSCB), a title that is already contained in rudimentary form in the alpha version of Longhorn. Quite possibly, the system will be able at some point to sort files that don't meet certain security criteria.