How do you gather and incorporate user feedback from Product Hunt into your marketing strategy?

First of all, not all of PH's community members would fit a product's target audience. So, making sure to filter out messages from people outside your target persona will eliminate a lot of inaccurate feedback. Of the ones that remain, you have to make sure that the user is actually saying what they mean to say. In consulting, there's the concept of "customer's voice" - the first job of a consultant is to figure out the gaps in customer's description of the problem, whether they're saying it right etc. Similarly, is the user saying it right? Are they describing it fully? In this way, develop that feedback fully. Ensure enough people have the same feedback, so it's not just 1 or 2 people saying it. Otherwise, you'd end up making changes in all directions. Only after all these can you actually implement it into your strategy.