Most PDA/PIM users sync or backup to their desktop/notebook computers if they backup at all. That's great if you use desktop PIM, it's OK if you use your own PC on a daily basis. I don't use any desktop PIM. Many people don't use personal computers at all; they use computers at home, office and/or school, but they don't/can't install extra software; those computers don't always offer reliable and private long-term storage. PC software/storage was partly replaced by web services (for some, not for me yet). However those web services are not really suited for use with the Z: small screen, not always connected, available browsers not Firefox/MSIE* compatible, ...
My idea is to connect the both: Zaurus/PIM to Web/PIM sync without need for a PC.
Is there any method known? I'm thinking of a PHP calendar/addressbook application which can be configured to accept all fields that OPIE/GPE have and offers a API. Then we can a write some software to run on the Z and connect to the web server by https. (Today you can usually get web access where ever you are, IP MASQ or mandatory proxies are not a problem. Servers that can run PHP/MySQL apps are wide spread.)
* I do know that Firefox does run on the Z and MSIE sucks.