Ask HN: how can I get user feedback without contacting users directly?

I'm working on a fairly large project building a business intelligence product for healthcare organizations. It's going well except for the fact that we have a minimal amount of user feedback. We haven't been able to contact users directly as that would be stepping on the toes of other divisions and when we get contacts from the "appropriate" sources they are typically useless. This roundabout method has also meant that we get in touch with a customer only about once a month and as I said, they tend to be useless (not our target audience).

Today, I decided to change this. While I can't actually contact users I decided that I would reach out on Quora and Reddit and find users who actually know a thing or two about Census metrics. So far, I received a few responses and I intend to ask different questions on these sites as well, provided I continue to receive helpful feedback.

I'm thinking, however, that there must be other methods to indirectly reach out to customers. Thus, I pose the question to you: how else can I get user feedback without contacting customers directly?

Thanks!