How email clients manage list threads (was: How do I set Midrange filters in Thunderbird?)

On 12/7/05, David Gibbs <david@xxxxxxxxxxxx> wrote:
>
> Dan wrote:
> > BTW, as an aside, I absolutely love gmail for the midrange.comlists!  The
> > threading is awesome, and I understand TBird offers the same thing.
>
> tbird's threading is nice, but not as comprehensive as gmail's.


I guess I'll have to see for myself what you mean.

I've always been curious how gmail threads these emails together.  It can't
be (just) by subject, because I've seen threads "broken" that have the same
subject, and I've seen threads that have the subject change in the middle of
the thread.

(If anyone reading this doesn't have gmail or another client that "threads"
emails, go to the midrange.com archives and look at a thread index for a
given month.)

When you reply to an email, there must be some unique identifier that came
with the email you're replying to, and it gets sent forward.  Reasonable
theory?

- Dan