I had a conversation with one of my suppliers regarding the510realm https://the510realm.com/.
He spoke with one of the site's admins and the traffic was still up, but content input had dropped. I think people are using message boards for research on topics more than supplying content.
FB has turned into the place to post projects and i think this is driven by the instant gratification it provides, but retrieval of technical information on FB is horrid. It may be because MBs generally stay on topic while FB posts are ALL OVER THE PLACE with many of the posts adding zero value to the topic.
If I'm looking for technical data and how-tos, MBs are the go to. If I want to sucked down the rabbit hole and see cats dancing in dresses, its FB all the way.