With Yahoo! Updates, sites can broadcast the activities of their users to Yahoo!'s massive global audience of over 500M+ monthly unique users. Sites integrating with Yahoo! Updates receive referral traffic from everywhere the Yahoo! Updates feed is published, including Yahoo! Messenger, Yahoo! Mail, Yahoo! Toolbar, and... even on iGoogle!
Users authorize sites to share their online activities on Yahoo! Updates using the OAuth protocol. OAuth allows users to authorize sites to access Yahoo! APIs on their behalf, without having to share their password. OAuth is an open standard supported by an increasing number of sites and makes it possible for developers to reuse code that implements API authentication without having to write custom code for every service provider.
To find out more about writing OAuth gadgets for iGoogle, visit Google Code.
Yahoo! Membership Architect