Just a suggestion. Why don't we have something like a "hottest" looking Forum award, or "Flarum of the month" ? I know we have a showcase, but having the devs pick out their favourite on a monthly basis would be a great way to increase engagement (and get a badge of honour on your own site 🙂)
As a reward, the owner of that site, could, for example, get 3 months of free subscription to a premium extension of their choice meaning they could try the latest paid extensions - a way of generating revenue for the dev who owns it as an incentive.
Just a crazy idea, but could well drive momentum, and an incentive to increase interest in Flarum. The "Flarum of the month" could even feature as a blog article......ok, getting a bit carried away here...
A sense of Gamification here, but....