On Thu, Jan 09, 2014 at 01:56:11PM +0800, lina wrote: > Hi Bob, my fault, I didn't realize this was a wrong way to start a new > conversation, by renaming the Subject and deleted everything inside. How > could they figure out it is from that thread?
Email headers include a field called "In-Reply-To" which contains the message ID(s) of the message(s) to which you're replying. If your email client gives you the ability to edit the headers, and if you had deleted the In-Reply-To header in addition to changing the subject, then everything would have worked out as you expected. On the receiving side, threading email clients use the In-Reply-To headers to construct a hierarchy of "threads" of discussion. The notable exception to this, as always, is Microsoft. Microsoft decided to ignore all the standards that the rest of the world uses, and only constructs threads by comparing the Subject headers.
