A new Thunderbird address book based on the CardDAV and vCard standards.
Correct Identity lets you better configure the default identity to be used when composing messages. When replying it can enumerate all your identities, thus not only those that belong to the account, trying to find the one that actually matches the addr.
Dawn will convert your address book from one program's format to another.
The Funambol Mozilla plugin allows Mozilla users to synchronize address book contacts and calendar appointments, between the Mozilla applications and the Funambol server (http://www.funambol.com), and therefore with any SyncML compliant clients, such as mobile phones, PDA, etc.