This card is also a little bit unique because it is a Maxi-card! I wonder if the sender is a stamp collector. Usually only collectors are interested in Maxi-cards. You may find that there is already a stamp with a special postmark on the front side.
Work for a Swiss company in Shanghai, East of Shanghai. Great passion for stamp, card and FDC collecting. Visited the Faroe Islands as lucky winner invited by Posta stamps. Do not hesitate to contact me if you'd like to swap with me.