thanks. I was wondering also. Does each group have an administrator or mod?
For the most part, yes. But on some groups, for one reason or another the mod may have quit getting on the site. In those cases, if the group requires approval to join and the moderator is not active on the site anymore, then you will not be accepted. On others that are "open to all", you get accepted right away, but can't upload photos. Well you can upload them, but they will never show up if there is not an active moderator for the group. Each group will have a listing for the mods, so you should check to see when they were last logged on, to determine if you want to join an unmoderated group or not. Some groups may not have an active mod any more, but the members still use the group for discussions, only can't add photos, which need approval from a mod before they can be added to the group photo album.