Nope!

It is illegal to open someone else's mailbox.

No. The inside of the box is considered USPS property. You can be fined.

Sierra,

While I agree that it is illegal to put anything in a U.S. Mail box, God forbid you ever own your own business, especially in this economy, and in desperation to try to keep the doors open you distribute a piece of paper or a business card to a house to try to generate referrals. And yes, it IS called advertising. When I receive flyers in my mailbox, or the newspaper box underneath, I glance at it, and if I don't need the service, I recycle it. I don't freak out at the "garbage" "these people" leave at my house. These are honest people trying to make an honest living trying to do it the most economical way they know how.

Calm down.

Mail goes in mail boxes. You're talk'n the Federal Government here

well if it is illegal, i'm sure i just got someone in trouble. just yesterday i opened my mailbox to find someone had opened it and put his business card in it. that was the last straw. it's bad enough these people leave their garbage taped and stuck to my front door every day, and claim to call it advertising. but this was in my mailbox. the kind you have to open up to put things in. not something with a little slot you can just drop a card in and never see the inside. i wrote a not to the postal carrier and stapled the card to it, asking the carrier to forward it to those who are able to take corrective action against the person who left the card. i've had enough.

It is in Georgia.

no...go to www.usps.com...it is a federal offense

I JUST MADE SOME FLYERS FOR A BUSINESS I AM STARTING AND PUT THEM IN PEOPLES MAILBOXES LAST NIGHT. THE POST OFFICE CALLED ME TODAY ALL BIGGITY ABOUT IT. THEY ACT LIKE THEY CARE ABOUT WHAT COULD BE TAKEN OUT OF SOMEONES MAILBOX BUT THE TRUTH OF THE MATTER IS THEY WANT THE MONEY THAT YOU WOULD HAVE SPENT ON POSTAGE. THATS ALL THEY CARE ABOUT. THEY COULD GIVE 2 SHITS IF YOUR IDENITY WAS STOLEN. AND WHO THE HELL IS GONNA STEAL SOMETHING FROM YOUR MAILBOX AND LEAVE A CALLBACK NUMBER. REALLY NOW????

I GUESS I WILL JUST FIND ANOTHER WAY TO ADVERTISE, OH AND I STILL WONT PAY FOR POSTAGE!!!

Everyone should know that you can't open another persons mailbox. But according to the law mentioned above, it sounds like you can't hang or attached flyers or such from the mail box receptacle itself, but can attach things to the mailbox post.