Erm, maybe I am misunderstanding what you are saying, but threading is a built-in feature of the email RFCs. Mutt can do it perfectly, and has been doing it for

Erm, maybe I am misunderstanding what you are saying, but threading is a built-in feature of the email RFCs. Mutt can do it perfectly, and has been doing it forever. If at all, it's a feature that was lost with some "modern" clients in the name of usability or something idiotic like that.