[Rattled]

Threading in email clients has been around for decades. Actually I must check if there are mobile versions of mutt or elm.

[porker]

And they thread properly. Unlike Gmail's bastardised 'We munge your subjects and think these are related'.

I considered implementing the Mutt threading algorithm in a browser extension for GMail. It's one of those "If I ever have less to do, I'll give it a shot" ideas that will never get done :)