Message threads are groupings of individual messages that share a common theme. A message thread consists of a "thread starter" and all the replies (and replies of replies!) that follow.
The "thread starter" is a top-level message that was created by a member about a certain topic.Once a thread has been started, it becomes an open exchange for others who wish to contribute their ideas and views about the same topic. When people reply to the thread starter, or reply to replies, they are building the thread.
The "thread starter" is created by clicking the "New Thread" button at the top of any messages page in the Community. When you create a new thread, it will become a part of the message board that you were viewing at the time you clicked the "New Thread" button.
When viewing messages in the Community, messages are displayed according to their organization within the thread. To get a general view of the thread, simply click the "View Thread Outline" link at the top of each messages page. The thread outline displays the subjects of all messages according to their position within the thread.