Sorry. There is no other alternative. It cannot be built without access to a social graph. I didn't think of including Twitter because of the user limits.
This is what is scaring away most of the site visitors. Each permission has a reason for being asked for:
"&scope=email,friends_about_me,user_about_me"
email: to notify you when a match is found. an access_token grants us knowledge of only the users email and not his friends'. This cannot be used for viral email harvesting.
friends_about_me: To seperate views based on gender.
user_about_me: to help decide which view is to be "initially " displayed based on the users' gender.
Well, frankly I wasn't expecting frontpage HN. This was just a sideproject that I was doing to get acquainted with golang. With respect to your concern about email address harvesting, the facebook graph api doesnt not give the app access to friends' email addresses. We only know the emails of the people who sign up, and it's used for notification purposes only. :)