Every e-mail I send to anyone, regardless of subject or recipient, will be five sentences or less. Like a cinquain. Ideally, it would be a 160 character count like an SMS message, but since that would require an actual e-mail plug-in (viz. “work”), we’ll go with the much-easier-to-count concept of sentences instead.
In order to politely explain the systematic brevity with a similar amount of brevity, I will link to a new site I just set up called five.sentenc.es in my signature line. By ensuring that all e-mails I send out take the same amount of time to send (viz. “not a lot”), I am evening the playing field between emails and attending to many more of them in the end.