By the way as an aside, I’ve been looking into other language communities where there could be more participation from the members. As my therapist says, I’m obsessed with performance and always try to find something better.
Duo Lingo: it continues to go downhill. Out of ten topics, one is language related.
Jisho forum: the last message dates back to 2015 so it’s pretty much dead.
Japanese Language Stack Exchange: an accurate and reliable source of information and usually with quick answers. Due to its format, it’d be impossible to run the activity over there.
Word Reference Forum: my first impression was that it was very martially run (as in military style). It’s not a bad thing, I mean, it has advantages but I’ve asked the moderation and it’d be impossible to run the activity there. Each thread must be about a single question/translation aspect.
Reddit: learn Japanese: I’ve never used reddit in my life but again, judging from the format, it wouldn’t be possible to run the activity there.
Japanese Page Forum: dead link, doesn’t exist anymore.
Japan Reference: very small active user base in grammar. I’m not under the impression this is where people would join in and participate in the activity.
Japanesepod101 forum: dead, hasn’t seen any activity for months.
Hiragana Ninja: dead forum, no activity in years.
And that’s about the first page and a half of google. I haven’t tested what comes on the second page but that often proves not to be worthwhile.