Address Book API was publicly launched today, it has already been in use at a handful of large partner sites, including LinkedIn and Plaxo. Charles Wu, the product manager for the Address Book platform, offered a number of use cases for the new API on the YDN blog this morning.Yahoo! today becomes the latest web BigCo to offer an API allowing developers to gain access to users' address books. Though the
Yahoo! joins Google, which released its Contacts API in March, and Microsoft, which released its own Contacts API, also in March. AOL is the only major web mail provider that has yet to open its address book to third part developers via API.
When Google pushed out the Contacts API we called it "the most in-demand API on the web" that hadn't yet existed. These APIs are important because they allow socially aware applications to offer users the ability to import information from their address books without having to worry about giving up their password to a third-party site. The application seeking the information also no longer needs to employ any screen scraping to gather information.
Like Google and Microsoft, Yahoo! opted to employ their own authentication technology in the API, called BBAuth. Yahoo! intends to supports OAuth in the future, though, which will make it easier for developers to use the API. "Support for OAuth is coming, my friends, in due time... Seriously," wrote Wu. "At Yahoo! we're already doing a lot with OAuth (think Fire Eagle) and it's a big part of our plans."
The API is currently limited to 5,000 queries per IP address per day.