I don't know where to post this, as it's not a suggestion, more a question.
When trying to share my forum with people directly concerned by its subject, they are all interested (sincerely, I think), but for most of them don't come back to it. And when I talk later about it with them, I always have the same answer: "I don't have the reflex to check it".
They basically explain me they are used to one common thread (like on facebook, instagram...) in which every of their subscriptions (to people, to chatroom...) is centralized, and therefore they don't have the habit to check something else from time to time. Most of them, for that reason (or others) don't use forums anymore. Maybe it's also why discord and reddit are more popular.
Sure, it's not a magical explanation for my forum (if a place is awesome, people go to it anyway), but I wonder it there were already attempts to think a solution to this? A way to centralize all forums in one, or even a way to integrate it inside another thing (facebook or else), even if of course it would just be links to the actual forums and threads (because I don't see how it could work otherwise).
I don't know it it existed for phpbb forums, and i don't see how it will be possible exactly. There are RSS feeds, but i don't know anyone who use them.