I admit that I hate junk mail, it makes up most of the items that I retrieve from our mailbox and I need to carefully extract the real stuff from its midst. There is no Opt out option for direct mailings in the US, although you can take register not to receive credit card offers.
However, without the volume of junk mail the US Postal Service would be in even worse condition than it is now. Junk mail represents 52% of mail by volume in the US, so is a vital part of their finances. Last year it lost $2.8bn and they expect to lose about $6bn this year. The USPS is considering ending Saturday deliveries as part of cost cutting moves. Earlier this year the Postmaster General warned that this was a possibility to a Senate Sub-committee.
Cutting a day from the delivery schedule might seem to have minimal impact on us as so little of our email is relevant; even the majority of our bills arrive via email. It would, however, mess with efficient use of Netflix, the DVD rental service. Currently it is possible to watch a DDV at the weekend, mail it back on Monday, receive a new disk on Wednesday, watch it and then mail back Thursday, receiving a new disk on Saturday for weekend viewing. This allows us to watch two disks a week, with one at the weekend. Cutting out a day of delivery would prevent such efficient use of our $8.99 a month payment