I can't seem to find any screenshots of how your app does what it promises to do. And the only way I know what it's supposed to do is because you told us in the HN submission, not on the site itself.
The first interaction is for me to type in some pretty sensitive information (email, phone number, etc.), which I am simply not going to do until I feel it's worth it.
Also: your site breaks in weird ways in Opera (10.60).