My local gym has running & cycling clubs and uses fb groups to coordinate events, provide a social area for members to share stuff, and maintains pages where th

My local gym has running & cycling clubs and uses fb groups to coordinate events, provide a social area for members to share stuff, and maintains pages where they curate important information for the group. FB isn't the only way to do this, of course, but it's certainly low friction for most members, since they generally already are guaranteed to have a personal FB account.