Retrieving user contacts

What is the best (and easiest) way to get a list of email addresses (preferably with names) for a user supplied email address and password for gmail, yahoo, hotmail, etc.?


Its better if you don’t do this. I wish no site actually did this.
Tired of getting crap invitations because my email was in someone’s contact list.

May I ask why?

99.99999% percent of the time I could care less what your selling. Then again I understand the marketing people love their worthless f**kin email blasts.

Not sure I understand. I want a user to be able to search my system to see if any of their contacts are already registered in my system. Sort of a social networking site. I don’t intend on emailing anyone.

I guess I could have them type in all the email addresses.