This is a tough platform sell because you have to tell people to install some other app to run/participate in your app. I've been through this, and it's tough to get other people to be your distribution channel. I created somewhat similar functionality into Notifo to do mobile surveys (but never launched it publicly). This looks like a much more fully-featured and flexible version of that idea, it will just be a tough concept for people that this lives inside another wrapper app.
EDIT: unless i'm misunderstanding completely, and you guys (tasty labs) will be driving the installs so as to create a mobile mechanical turk force... in which case, this could be communicated better in the copy. Now I'm just confused.