There is nothing special about contact/address book information.
There is no reason you can not store contacts, tasks, calendar items,
... In any IMAP server you choose. All they are is specially formatted
messages.
The Problem is that there are no IMAP clients that can properly
understand and treat those messages as contacts, tasks, ...
With enormous difficulty it is possible to view contacts etc.
stored on an IMAP server with Outlook 2000. But it is not possible to
edit them or save new ones. I had hopes that Outlook 2002 would resolve
this - but it actually made the situation worse. You can not even
succeed in viewing a contact on an IMAP server.
Outlook actually goes out of its way to have less functionality
when talking IMAP than MAPI.
