This is a loosely controlled collection of discussion groups. A message (similar to an e-mail) is posted in a specific area and then people can comment on it, publicly replying to the same place ("posting a response") for others to see. A collection of messages along the same theme is referred to as a thread. Some of the groups are moderated, which means that nothing is posted without the approval of the "owner." Most are not and the title of the group is no guarantee that the discussion will be related. The "official" term for this is Usenet News.