Just a thought from someone currently working on marketing his own firm online:

Ideally, your existing customers would be so happy with your product, that they would write about you in those forums. Could you help them do that, or lead their attention to it? Or - if you think that is unethical - could you respectfully recommend your own product in the forums?

Alternatively, you could just participate in the discussions and add value like that. You could learn about how your competitors work from their customers perspective, and get new ideas for your own product from the interaction.

That way, you would get both visibility and ideas for product development.

Good luck with your branding! Feel free to set up a call if you want to discuss the idea more in depth.

Best regards
Kenneth