I got very few people who sign up (which amount to choose a login and a password, no email required), I think it was around 10. Only one person tried really the service (i.e. uploaded an SSH public key and uploaded a few files).
The interesting thing is that even when the post had slipped from the front page, it was still generating a bit of traffic, possibly doubling the number of person registering.
The best thing I got from that post though was some feedback on HN itself but also a couple of persons sent me an encouraging emails. For that reason alone, even if you're not ready (you never are), post publicly your work as soon as possible.