Allow "opt-out" of junk mail. In Europe you can put a sticker on your mailbox. No more junk mail.

To allow citizens, not business, to decide what arrives in your mailbox. An official sticker that says "No Junk Mail" on your mailbox is all it takes - EXCEPT that it is not up to you, the individual, but it should be. Imagine the savings in resources if just half the junk mail is stopped.