Found this online
E-mail takes too long to respond to, resulting in continuous inbox overflow for those who receive a lot of it.
Treat all email responses like SMS text messages, using a set number of letters per response. Since it’s too hard to count letters, we count sentences instead.
three.sentenc.es is a personal policy that all email responses regardless of recipient or subject will be three sentences or less. It’s that simple.
* See also: two.sentenc.es, four.sentenc.es, and five.sentenc.es.
** To begin using this system, optionally copy this text and paste it into your e-mail signature: