Are discussions automatically archived from the Chat room?

No, chat rooms are not automatically logged. You can turn logging on by selecting the action menu next to the chat icon and choosing EDIT PROPERTIES.

At the bottom of the PROPERTIES window, choose MORE OPTIONS.

You will see a check box you can select to turn on chat logging.

Selecting this option will enable recording of all chat room activity until you uncheck it.

You can view the logs by slecting the ACTION MENU next to the chat room icon and choosing VIEW LOGS.