[happyfeet]

As most people say, you can launch a half-feature not a half-assed one. If you think you have the minimum features necessary to make your app 'useful' for your initial customers you should just launch.

I do not see a blog link on your webpage. If not, start doing it soon. Start talking about your app, use cases, problems and how you are solving them. Anything that you think is relevant for your broader audience.

And iterate based on feedback from your initial customer base. Don't worry right now about scaling. If you have that many hits on your app that is a good problem to have. The worst is indifference.

Good luck with you app and I am sure you'll do well.