What are Audiences used for?

Audiences have two purposes:

1. Targeting questions

You can attach an Audience to a Question to limit who is eligible to be asked the Question.

2. Question response segmentation:

Regardless of what (if any) Audiences you attach to a Question, you can retroactively segment responses between different Audiences. You could, for example, ask a very simple question like "Are you willing to give us a quick testimonial" and then segment responses between your Free Tier Audience and your Paying Users Audience to see if your paying customers are willing to give you testimonials.