I'm a dedicated GMail user, but I think it's good to give credit where credit is due. Autosave was definitely not first in GMail. Thunderbird also allowed mess

I'm a dedicated GMail user, but I think it's good to give credit where credit is due. Autosave was definitely not first in GMail. Thunderbird also allowed messages to be sorted by thread a while back (which you could argue was a rough precursor to GMail's conversation view).