> Trailing whitespace gets lost easily in editors. As far as I'm aware, mail clients typically don't modify quoted text beyond prepending each line with a > ch

> Trailing whitespace gets lost easily in editors. As far as I'm aware, mail clients typically don't modify quoted text beyond prepending each line with a > character. Even if the trailing whitespace is lost, then you'll just have a conventional hard wrapped message (which is no different than just using a mail client that doesn't support format=flowed). > The concept of "format=flowed" itself can get mangled if someone with a mail client that doesn't support it replies. Not in my experience. If they remove the trailing whitespace, then it's essentially hard-wrapped again. If they don't, then it's still flowed. > And yes, people do send things like ASCII art or underlined text or code or other things where whitespace and wrapping matters. In that case, the flowed option isn't suitable. The RFC I referenced does support a fixed option for the format parameter which would address that issue. Also, Thunderbird did not attempt to append whitespace to previously quoted material if it didn't have it already. In any case, the flowed format would work perfectly for this particular thread since no one is hard wrapping anything.