If the linear style option is chosen by the administrator, the thread will display the replies in the order of their response date. Subscription is a feature that lets register users periodically receive email notification of new messages. As a registed user, you can choose to select one or more forums to subscribe to. To subscribe, select user menu icon from the Lobby or the Main Listing. Or, you can just click on the subscribe link in the main listing.
Public forum is where everyone can participate without registration.
Everyone is allowed to read and post new threads. That is, if you want to post your own messages, you must first register. In order to access the forums, however, the moderator of each forum must grant access on user to user basis. When I post a message in one forum, it posts ok. But in another forum, it won't post.