Today, Yahoo! announced the release of the Address Book API which enables developers to interface directly with one of the largest “collection of address books” on the web. This is an incredible release moving forward the opening of the social web. So what can you do with this new API? “Once a user authorizes your application, youÃ¢â‚¬â„¢ll be able to easily access that userÃ¢â‚¬â„¢s address book and look for specific contacts.”
If you think of this in relation to a Facebook application, it is similar to having the ability to browse through who a person’s friends are and directly contact those friends. The only difference is that this API provides access to potential emails and phone numbers, something that Facebook has fiercely prevented developers from accessing. Currently no social platforms enable such open access and it is great to see Yahoo! take a leadership position in this movement.
One example of this in practice would be an invite form that enables a user to invite their friends to join them on your site. Rather than using the default invite form that Facebook provides within their walled garden, you can have users select email addresses and phone numbers to send out invitations to their friends. This means that you can take your contact list with you anywhere on the web.
When a user comes to your site they will simply need to grant access to that site to have access their Yahoo! address book by logging in via the standard Yahoo! login screen. Once they login they will be redirected back to that web site/application which will now have access to their contacts. This form of authentication is called BBAuth and you can read more about it via Yahoo!’s BBAuth documentation.
If you are a developer and would like to learn more about the Address Book API you can read about it via the Address Book Developer Guide. Also, I recommend watching the following interview with Joseph Smarr of Plaxo that John McCrea posted. Joseph is one of the most articulate people in the industry about social web standards.