what a stupid suggestion. emails have subjects for a reason - they summarize the email for the recipient. if you are constantly using email for such short communications, you should probably be using some other medium like jabber. or if your email is short enough to put in the subject, then just put it in the subject. back and forth replies will keep the content in the subject rather than getting trimmed off and having a thread based on "subject: hey".<p>if an email arrives and i get notified on my phone with just "subject: hey", i'm forced to unlock the phone and read the message just to find out what it's about, rather than being able to see "subject: conference call next week" and know i don't have to read it right away. also, when i have to dig through my email archive a week later to find an old email, i don't want to have to read a dozen emails all titled "hey" trying to find something.
Personally I've always wanted an E-mail program that would let me <i>edit</i> any message in my mailbox. Why should I be forced to organize my mail according to the poor subject lines that someone else used? And given no subjects at all, I'd be even more interested in having an editing feature.