I use Notes as a POP3 client for my internet mail. Problem is that this does not allow me to look at previously-downloaded messages unless I am at my home PC.
Notes works as an IMAP client, supportng both offline and online access. This would seem to neatly solve the problem. Kust switch from an ISP that offers POP3 to one that offers IMAP, set up an account document to point to it, and voila, all messages should stay on server even after downloading to Notes, oldmessages should migrate their way up to the server, and any changes I make on one side (folder moves) should be reflected on the other.
Ir didn't work as planned.
Try diong this yourself, see if you can get it to work. I used mailSanre.com, which offers a 30-day trial of their service, and offers IMAP. They have a webmail interface that also makes use of the IMAP protocol on their own mail server -- http://www.mailsnare.net/horde
See if you can get offline setup to work at the very least, with folder replication, and preferably upload of prior messages. I have to get this working for a client soon.