Technically, it is like threads, but it includes messages from other directories that belong to the thread, thus showing you the whole coversation including you

Technically, it is like threads, but it includes messages from other directories that belong to the thread, thus showing you the whole coversation including your answers and archived messages. Graphically, it shows all the messages in a continuous stream as opposed to only one message at a time. Since you now see all responses at once, there is no need for quoting any more, so quotes are collapsed. I don't use Gmail any more, but conversation view is all but essential for me, too.