Once again ... and the answer is still the same. No, no, you cannot create a folder in POP3.
There is no such thing as a POP3 folder.
POP3 is for retrieving messages, not for managing remote storage.
See http://www.landfield.com/rfcs/rfc1081.html
Mail clients that use folders (in other words, Eudora, Outlook, Netscape mail, et cetera) to organize mail do so on the CLIENT side, not on the SERVER side.
They do NOT use POP3 to manage folders. They may use POP3 to retrieve mail, which then is sorted into local folders.
If you want to build a Web-based mail client that supports folders and pulls mail from a POP3 server, go right ahead. (Or download one of the many that already exist.)
You will need to create a storage system for the retrieved mail. That's how most commercial Webmail systems (Yahoo, et cetera) support POP3.
The application on the Web server acts as a POP3 client. It fetches all of the mail and THEN sorts it into folders. But they are not POP3 folders. They are local folders (from the point of view of the mail application).
IMAP works on a completely different model. It leaves all of the mail on the IMAP mail server. It allows for organization into folders, et cetera, on the SERVER side. Using IMAP protocol, the client looks into the server to see what mail is available. It does not retrieve the full mail item until you click and read it, one item at a time.
If you had an IMAP server and you built a Webmail client for it, you could access exactly the same folders, the same physical storage, as you would see if you connected to that IMAP server through Outlook Express or Netscape mail.
This would be true regardless of which computer you used or where you were physically located. That's the point of IMAP. It can't be done with POP, and that's why IMAP was invented.
