Unthreading Gmail

Google mail has just recently added the ability to turn off the message thread. Which I think is great, that you now have this ability.  Although the initial threading of a conversation for those coming from Outlook, or so I have found, seem to have troubles with this so yes, it would be nice to turn it off, but I don't think as much to be going back to the 'classic' look, but to help ease someone from getting out of the Outlook way of thinking. There are times when the conversation threat gets broken, mostly due to someone using Outlook, simply goes back to a previous message that had a completely different topic, and sends out a new message in that method. This is where the ARCHIVE feature helps keep the person from seeing that previous message to simple open and REPLY to it.   My question would be, if I choose to turn it off, does this now break the thread, should this person choose to send a message from a previous response, can you then turn it back on and see what thread it was from?  Only way to know is to give it a test I guess, but that is the great part about any software program that allows you these options.  FACEBOOK could learn a thing or two from this.