202212160543.AYC Re: eMail Conventions

Fri Dec 16 17:27:55 UTC 2022

On Fri, Dec 16, 2022 at 9:05 AM ic <lists at benappy.com> wrote:
> In my experience, threading is done by clients looking for the In-Reply-To: header, not subject. Subject is a heuristic fallback, in case In-Reply-To is absent.

Correct, they use the In-Reply-To and References headers to thread the
emails. Subject line change is a heuristic, not for threading the
emails but for -breaking- the thread. It's a good heuristic. Unless
the sender is doing something asinine, changing the subject line
signals their intent to start a new conversation.

Regards,
Bill Herrin

-- 
For hire. https://bill.herrin.us/resume/