[alain94040]

Spam filters are a major issue, but it wouldn't explain why only 5% of people you ask reply.

On the other hand, these are people who signed up, probably curious to know what your site was about, and then they saw and decided it wasn't for them. Not much you can do at that point.

Have you been receiving complains from people you email?

[aderaynal]

Very few complains, In fact I wish I had more ;) My product is not spammy, It provides a great service, but I know I need to do a better at educating new users. It tough to do when my emails do not seem to reach them...