[wp-hackers] PROPOSAL: Use sunmanagers etiquette to help reduce list S/N ratio

[Jeremy Visser]

DD32 wrote:
> Emails contain a "In reply to" header, thats how most mail clients
> thread emails, Not sure if gmail follows it. Sometimes mail clients
> dont set the header which causes it to break the thread in some mail
> clients(ie. opera). I have a feeling Gmail uses a combination of the
> header and the subject if its not available.

Gmail only threads based on the subject line. If the subject line is 
changed, it breaks the thread. Google Groups does not do this, and I 
wish Gmail worked like this: when the subject line is changed, the 
message is displayed in the same thread, but a yellow is noticed with a 
message like "Jeremy changed the subject line to 'Foo Bar'".

Thunderbird and Evolution thread correctly regardless of the subject line.