I believe that Steve Jobs was one that practiced this when dealing with customers. And it seamed like his responses were always dead on target - whereas a PR team would launch into a long winded response to a customer, Steve summed it up in one sentence.
I've seen people who are great at short emails... but I've also seen a lot of miscommunication when people shoot fragments back and forth. It's a fine line between concise and useless.
That surely drove Apple's PR team crazy...