The author claims he prefer having the application/OS hide the classic filesystem hierarchy from users (he presents the iPhone OS as an example).<p>While the idea works for a small number of 'files' (or documents), it does not scale well.<p>When you have a few tens of files, you need some way of organizing them. Search solves part of the problems, tagging and 'folders' are another option (see Gmail labels and Google Docs support of folders).