CardDAV is much like CalDAV and WebDAV - but for vCards - which has been around pretty much forever.
Interesting fact: Apple appears prominently in the RFCs of two of the three protocols as well as the vcard format.
With vCard and CalDAV, open-source productivity software never really did much better than Microsoft Exchange/Outlook, but CardDAV does provide something that Exchange doesn't - an working, standards-based way to sync your contacts across all accounts.
http://tools.ietf.org/html/rfc6352
CardDAV is much like CalDAV and WebDAV - but for vCards - which has been around pretty much forever.
Interesting fact: Apple appears prominently in the RFCs of two of the three protocols as well as the vcard format.
With vCard and CalDAV, open-source productivity software never really did much better than Microsoft Exchange/Outlook, but CardDAV does provide something that Exchange doesn't - an working, standards-based way to sync your contacts across all accounts.