First: I don't know what the app does. Not in technical terms, but what problem it solves for me. Imagine your ideal customer. Imagine his itch. And then imagine, that you have less then 5 seconds to tell him, that you solve his problem.

Even after reading the comments on HN, I do not know, if it mails me the reviews I wrote, or the reviews, that anybody wrote on my app.

If it is the 2nd, I could imagine a use-case, when I look at my workmates, who manage our apps. They might be users. But I would not tell them of this service, as I did not understand it.

Else:

- Sign-Up-Button(Call to action) below the fold. - Get a lot more feedback on Design-Iterations from people outside (so the HN-Post was good) - A|B-Test your Design (For example with Genetify: https://github.com/gregdingle/genetify/wiki)