Isn't this exactly what UIDocumentInteractionController, etc accomplishes? [0] Each application registers the data types for which it is a "viewer". Applicati

Isn't this exactly what UIDocumentInteractionController, etc accomplishes? [0] Each application registers the data types for which it is a "viewer". Application with the content provides a way to open the document interaction controller with reference to the document, iOS supplies icons of apps that can open it, user selects app and it opens with a different launch options so it opens the content directly. There is nothing more fine-grained than file-type but mime-types, win32 registry keys, etc have always just been conventions really outside of a few well-known types. BFS (beos) tried to add in metadata attributes to the filesystem and it was pretty slick, admittedly. I guess I can kind of see the complaint about wasting space on duplicates but if one app is a viewer, and the other is an editor... well I think the OP comment is kind or obtuse. Sandboxing files is a much better approach for lots of reasons. Apple made the right decision, let each application organize access to its information in the way it best sees fit. If it's a tree view, ok if it is some skeumorphic bookshelf, ok. [0]: http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIDocumentInteractionController_class/Reference/Reference.html http://developer.apple.com/library/ios/#documentation/UIKit/...