I totally missed this app the first time around, but PaperKarma is an iPhone/iPad app and Android app that helps you stop junk mail. Catalogs, magazines, coupon books, flier, credit card offers, yellow books, etc.
You just snap a photo of any piece of unwanted mail, and that’s it. (Try to capture the address label and any tracking codes.) They scan the photo, grab the pertinent details, and contact the mailer directly to remove you from their distribution list. They’ll even contact you when you are successfully unsubscribed. For free. That sounds almost too good to be true.