We do have a question that came in: Was the opt-in pop-up triggered through a ReachOut campaign, or was that hard-coded in the example you just showed?
Effectively with this particular case you will be collecting the data as a custom property so you want this to be hard-coded in your application. That way, as soon as your application loads you want to pop up that that request to the user. And then, when the user answers the question, you would save it as a custom property via the custom property API called.
This is mainly a hard-coded version there are options by which you can be more elaborate and have a ReachOut-generated feedback pop-up, but for this particular case it's much easier much simpler to have a hard-coded version.