I have seen some site started using this wonderful technology for invitation purpose..
What it does it to prompt user who wanted to send invitation link to his / her contact of friend to enter their yahoo/gmail/hotmail/aol ID and password..
Once done the system able to retrieve contact / address book for the particular account provided IMMEDIATELY!!!!
This shouldn't be done manually as the password entered shall not be stored in any form and shall not be fwd to anyone for manually retrieving purpose..
Anyone familiar with such technology? I tried to look around the web but couldn't find any info so I turn up here...