agreed that it's not broadly useful to have discussions that aren't seen by people who want to see them. It's a two-way problem, keeping SocialHub in the loop and keeping everybody else in the loop as well. It's a good example of what I was talkingn about in the other thread: it's useful to get input on the question of whether or not SocialHub discussions are currenlty meaningfully "on the fediverse" from people who don't have SocialHub accounts!
I'm not sure you need to be able to fully pull in discussions that are happening elsewhere ... for example a link aggregator that combines links to interesting discussions elsewhere with discussions of its own that others can participate isn't as smoothly integrated but could still be useful.
Being able to have threaded, categorized long-form discussions that people who have accounts elsewhere can broadly participate in certainly seems like something that a lot of people want. If that's not possible with current fediverse software then (a) that's disappointing but also (b) now's as good a time as any to work on improving it and this is as good a use case as any.
By contrast it seems to me that most of the potential audience doesn't want non-federated threaded, categorized long-form discussions enough with the people currently active on SocialHub to participate on any kind of regular basis on SH.