In Holland they have a system for this.
The post office will give you stickers that say either 'Ja' or 'No', in various colors for various kinds of unsolicited mail.
You decide if you want junk mail or not, and what kind (commercial, political, etc).
Businesses caught violating the stickers are fined, and the consumer gets a cut.
You see a lot of 'no' stickers if you look at the mail boxes.