I can put documents in my iCloud, but they are just dumped there. Can I create folders so I can organize the documents? The help page seems to indicate so (it talks about renaming documents and folders), but I don't see a way to do it. I tried to move a folder full of document from my desktop to iCloud, but got a message that the file format (of the folder) is not supported.
Being able to organize documents into folders would make the cloud much more usable for document.
When you open or save a document to iCloud, you can create folders by dragging documents onto each other. That will create folders in iCloud, for example in TextEdit, when opening a document with "File > Open":
Drag one icon on top of the other and select the heading "Folder", then enter a name for the folder. The same will work with Pages or other iCoud applications.