I have always been fascinated by this postcard that someone sent from Australia to the U.S. back in 1993:
First, it's a picture postcard with the Kangaroo; second it has the 90c Australia Kangaroo stamp affixed with FDOI cancel; and third it is a conventional postcard valid for mailing, as the reverse has the following imprint:
They were apparently issued by Australia Post at the time. Does anyone know if similar ones are still issued today? It seems a rather novel approach of being able to send a friend or family member an international postcard and at the same time expanding one's collection with a stamp bearing a first day of issue cancellation.