Junk Mail: how to lessen the deluge

Wire and Twine present 50 simple ways to help the Planet. They suggest things like-
hang clothes to dry
use both sides of the paper
brush your teeth without letting the water run
cut down on junk mail

It's the last suggestion I need to do something about. If I lived in the US I could sign up with GreenDimes, a simple effective one step answer. In Canada you have to do a lot more work.

First- paste a sign saying, No Junk Mail, on your mailbox. Second- sign up with the Canadian Marketing Associations do not contact service.

I really hope it works. I'm off to walk up the road to paste a sign on the inside and the outside of my mailbox.