TechNayak(mirror)

Yahoo…..make your application use data from yahooo accounts of users. A new authentication mechanism by yahoo lets you retrieve yahoo data( i think its data like contacts, calendar, briefcase, photos) by redirecting users to their secure yahoo login page. Once in the page the user has to enter their credentials and allow for you ( 3rd party site) to access his/her data. You will have to register your site with yahoo however to be able to use this service and its BSD licensing(FREE). Pretty cool I must say.