As a holiday gift, Carolee supplied Kathy and I with copies of a lovely book by Edward St. Paige entitled Writing Letters with Pen & Ink. It was a fantastic gift- the perfect thing to curl up with on the couch in this -17 degrees Fahrenheit weather. [Seriously, my nostrils froze together this morning.] It's mostly a collection of quotes and images of paintings of letter writing, but there is some handy information about ink and paper choice as well.
Tucked in the back was the best part of the book; a little explanatory guide to the language of stamps. Now, up to this point, I had been unaware that stamp placement could also be a way to communicate. The practice appears to have originated from people placing special code marks on the outside of envelopes in England during the time when recipients of letters paid for their postage. Basically, the marks made it so that people could scam the post office. Later, when postcards became in vogue, the stamp language became a way to submit information clandestinely when the postman could freely read your words. Marketing geniuses screwed it up though, when they began publishing postcards with the language decoded on the front. Also, many of the placements involved other sections of the envelope other than the upper right corner, which is required for mailing today. Nowadays, you mostly find the language in use in military post or having originated organically between pen pals. The positions have different meanings depending upon what language you speak as well; a "kiss" in Finnish may mean "write soon" in English.
Here's a selected list of meanings according to The Philatelic Database:
Upside down, top left corner = I love you
Crosswise on top left corner = My heart is another’s
Center of envelope, at top = Yes
Center of envelope, at bottom = No
Straight up and down, any position = Goodbye sweetheart
Upside down, top right corner = Write no more
At right angle, top right corner = Do you love me?
At right angle, top left corner = I hate you
Upright top right corner = I desire your friendship
Upright in line with surname = Accept my love
At right angle in line with the surname = I long to see you
Centered on right edge = Write immediately!