Portable Contacts
Portable Contacts was an open protocol for developers to make it easier for developers to give their users a secure way to access the address books and friends lists they have built up all over the web. The goal of the project was to increase data portability by creating a common and open specification to bridge proprietary contacts Application programming interfaces such as Google's GData Contacts API, Yahoo's Address Book API, and Microsoft's Live Contacts API. It combines OAuth, XRDS-Simple and a wire-format based on vCard harmonized with schema from OpenSocial.
The editor of Portable Contacts specification was Joseph Smarr of Plaxo and the project co-maintained by Chris Messina.
Portable Contacts was used by services such as Google Contacts, Windows Live Messenger Connect, as well as other specification such as OStatus.
