I found this curious item this morning, and was wondering if anyone could shed some light on how these were used and produced? I purchased it, but don't yet have it in hand and there's no picture of the reverse of the card. Would there be some kind of postage on the card, and if so is it provided by the person sending in the card or by the business using these? Printed to Private Order or Stamped to Order postcards. All I've been able to find so far was a minor mention of them in the Manual of Philatelic Judging.