Ask IH: What questions generate great discussions in online communities?

What's the right way to provoke or generate discussion by asking questions in online spaces? I'm thinking of founders trying to learn from an audience / online community to assess the need for a new product. I'm NOT thinking about pitching/marketing a product.

The reason I ask is, my co-founder and I have a product that we think might be a good fit for a certain industry. We hit up some contacts to get interviews going. We managed to speak to one or two people, but found it hard to get more given we don't have strong connections in that industry.

We decided to turn to online groups on linkedin, reddit, & facebook. We tried asking a question in a post to generate discussion. Our plan was to see if there were any particularly interesting answers, then follow up with the responders.

Generally our posts were along the lines of

• title: "how do you do X?"
• body: "hey <group>, how do you do X, what kinds of tools and processes do you use? We're thinking of building a tool to help with X, but we'd like to know more before we do."

We've posted a few times but so far -- crickets!

What confuses me, is that I've done stuff like this before, and I've had ok responses. Thinking about social media / online communities in general, it has always been unpredictable which posts generate engagement!

On a weird meta-level, I'm now wondering how well this post will do here on IH!