I think these are mostly the more loose groups, the "real" communities are still in the forums. The more niche / dedicated it gets the more likely is it to have a forum.
To be fair I only have experience with old car restoration groups but there may be some FB groups where people post selling / buying things but the real discussion is still in old-school vbulletin style forums.
To be fair I only have experience with old car restoration groups but there may be some FB groups where people post selling / buying things but the real discussion is still in old-school vbulletin style forums.