The Email Charter is a great idea.

We’re drowning in email. And the many hours we spend on it are generating ever more work for our friends and colleagues. We can reverse this spiral only by mutual agreement. Hence this Charter

The rules are these, they are explained more at the site.
1. Respect Recipients’ Time
2. Short or Slow is not Rude
3. Celebrate Clarity
4. Quash Open-Ended Questions
5. Slash Surplus cc’s
6. Tighten the Thread
7. Attack Attachments
8. Give these Gifts: EOM NNTR
9. Cut Contentless Responses
10. Disconnect!

Follow as many of those rules as possible and the (email) world will be a better place.