Yeah, but you have to remember about one of the most important Open Source rules - when they close the door, we enter via window 
Anything that is not explicitly forbidden in ToS is allowed, right?I doubt that they’ll change their APIs and methods again just because some discussion software community found some loophole 
I’d like to ask you about Telegram Notifications Plugin (discourse-telegram-notifications) : it interacts with Telegram bot when regular 
notification is created, is that right?
About the notifications - yes, they are available for every app, and if we’d combine it with embedding instance as a FB canvas app, we would escape the TOS, as redirecting users out of faceook by app is explixitly forbidden. And I still remember, that making canvas app out of regular website is rather straight-forward, I did something like this with Drupal once.
Perhaps we could use the “invite friend to this app” mechanism as well? Combined somehow (or not) with built-in invitations system?