There's a web site Five.Sentenc.es that espouses the practice of never sending an email message longer than (you guessed it) five sentences. There's also four.sentenc.es, three.sentenc.es and for the truly brave (and brief) two.sentenc.es.
The idea is that you adopt this practice, and then put a link to your sentenc.es of choice in your signature line. (Ostensibly so that when your email recipient wonders why you responded to their complex list of questions with five sentences, a ready explanation will be visible.)
I like this idea, but I still wonder if it is unrealistic. Recently (especially since switching over to Gmail) I've also tried doing the Inbox Zero thing. It's not too hard, but I do sometimes forget messages I overzealously archived too quickly.
What I've been telling myself with email is that I don't need to be artful, I need to be brief. Anything longer than a paragraph or two won't be read. And if it takes me longer than five minutes to compose it, it needs to be a phone call. (Unfortunately, I usually figure this one out after I've sat trying to infinitely compose an intricate email.)
For email, less is more. Wouldn't you agree?
I think there are two different types of e-mail. For most, e-mail at work can be five (or fewer) sentences, particularly if it's of the "did you get this report" variety.
For the rest, however, it's a form of snail-mail or memo. When I'm corresponding with my friends, for example, we no longer physically write (well, I do but they invariably respond electronically). Five sentences would not be enough.
I know what you mean! I know I don't read long emails...I try to keep mine brief or reformat (e.g.an FAQ). I hadn't heard of the 5 sentences movement before, I'll have to check it out!