Originally Posted by JSWolf
If the Kindle ignores folder, why try to use them?
The Kindle shows all ebook files in the Documents folder or any subfolders thereof. It presents all of these files in a single list. However if the ebook is or a certain type it displays the ebooks with that type with the same "Title" as a folder on the Kindle home screen. This is used for the newpapers and blogs if you subscribe. As others have figured out, if you just change the book type on ebooks you get the same behavior. This happens not matter what file system folder the ebook files are in. They can all be in the documents top level folder and will still display on the home page.
If this can be done, and you prefer it, why not do it?