[LMStone]

Zimbra's view is that for public access computers, the web browser is the best way to go. Zimbra can be configured to do everything over https, and unlike Outlook Web Access, the Zimbra Web Client has a full feature set.

Zimbra Desktop is like a mini Zimbra server. It provides offline access (like Outlook in caching MAPI mode) and has pretty much the same feature set as the full web client. You could not however make a completely portable copy of ZD, in the same way that you can't install Outlook to a USB drive and run it on any Windows computer.

The Zimbra server Network Edition has built-in backups, which can be pointed to a separate machine over NFS, iSCSI or FC. There are community backup scripts for the free Open Source version of Zimbra as well.

I understand why you are using your USB stick with pst files the way you do currently, but I think you will find with Zimbra you can lose the USB stick and not sacrifice any portability nor data security.

Hope that helps,
Mark