If it where no walled garden, then I could reach the chat rooms at conf.hipchat.com from e.g. my gmail account. As the linked page says "Our server is not feder

If it where no walled garden, then I could reach the chat rooms at conf.hipchat.com from e.g. my gmail account. As the linked page says "Our server is not federated and will not let you send or receive messages with users on other networks."