As far as I understand it, your service collects email addresses from the web and then enables your customers to access that email database. In some European countries that would probably be illegal - in others it would be legal, but bordering on unethical behavior (the fact that someone - probably by accident - publishes his/her email on the web doesn't mean he/she wishes to be spammed).

So the fact that you even managed to get six signups for your email database is quite amazing (and I don't mean that in a good way), and I don't think those who make proper, ethical startups have anything to learn from your experience.