A relevant tangent was discussed a bit ago, with using trust levels to “reward” users who post to particular categories, or not reward at all when posting to other categories.
https://meta.discourse.org/t/disable-categories-topic-from-the-user-statistics/34717/6?u=purldator
General discussion boards and participating on them would offer no in-system incentive with this idea of mine. But these off-topic boards do offer a needed psychological-related outlet; one I feel every niche discussion community should have if it wants to survive for very long.
This may be part of a sound remuneration strategy: “Why should I post on-topic and offer free original content for google to attribute to your website. Give me incentive to stay. Oh? I can make friends who be as passionate as I on this same niche topic, and talk off-topic on other subjects to mix things up a bit? I’m game.”