13 Jan
                
                    2012
                
            
            
                13 Jan
                
                '12
                
            
            
            
        
    
                2:07 a.m.
            
        Changing the subject won't start a new thread of discussion; the "In-Reply-To" headers preserve the thread regardless of the "Subject" headers of the messages. It's preferable to use the "compose new email to this address" feature of your email client instead of "reply".
Cheers, Andrew
OK, I'll bear that in mind.