<< Autopsy...
Those are return receipts from the post office.
You can send an item with a return receipt card attached to it. When it is received, the card gets signed or stamped, and the post office returns it to you. You then have confirmation that the item was received.
I personally don't do this as I copy EVERYTHING that I send in, and have never had a problem. >>
Yeah, I copy everything religiously as well. But, for me, when I have rebates $75.00 or over I do the postcard thing. Just as a little insurance. Never needed it, but the time I stop is the time I'll get bitten . . . . what a world what a world.