Early Marketing for an iPhone weight loss app

I recently launched my first iPhone app. It's called AdiPosse. It's a body weight tracker with social networking built in. Basically twitter, but instead of posting 280 characters you just post your bodyweight every day, and an optional note.

I've been in the app store for a couple of months, but most of my current user base is from my personal social network. Engagement is fairly good. Now I'm looking for a low cost way to acquire my next wave of early adopters.

What are some good free ways to do this?

I've never done a ProductHunt launch before. I don't know if I want to use it yet, or wait until I've finished all the important features in my backlog.

#ask-ih #growth