Creator: Not really sure who created? If you know add a comment below so we can honour them.
Purpose: A personal policy to help manage your email.
Manifesto
The Five Sentences Manifesto
The Problem
E-mail takes too long to respond to, resulting in continuous inbox overflow for those who receive a lot of it.
The Solution
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.
five.sentenc.es is a personal policy that all email responses regardless of recipient or subject will be five sentences or less. It’s that simple.
Source
Core: http://sentenc.es/
Specific 5 sentence version: http://five.sentenc.es/