There is this page on Facebook:
https://www.facebook.com/subterfugegame/But it looks like it's mainly retweets being reposted. (I'm not on Facebook so maybe it looks different for you)
But there have been various platforms started by users (the Wikia, a Kik messenger group, a Russian community I believe), so go ahead! Please post here if you do.
I've been thinking about a Whatsapp group (that's what I use a lot) but then you'd need one moderator to add people, and everyone has to share their phone number. A Facebook group could be a great idea and fits the goal better.