I'm not sure exactly why this is. But I reckon it's got something to do a concept JJ Abrams (creator of 'Lost') calls "the mystery box".
When you have a moment, have a look at a seminar Abrams gave on good storytelling - link is below. He talks about being drawn to things which have "infinite possibilities" and uses the example of a box of magic tricks he is fascinated by because it's never been opened.
For me, postcard messages offer a similar means for firing imaginations. They might be a bit pedestrian, especially compared to special-effect-driven adventures on desert islands, but mysteries are there to be enjoyed.
And with coded messages you get double your intrigue.
The code presents the obvious challenge, working out the words the author wanted to hide from the postman. But even when you've deciphered the message you are still only left with one moment, one piece of a dialogue. The before and the after remain hidden.
So, to this week's cards. I've put two up. The card in block capitals is at the Easy end of the code spectrum. If you're struggling there's a clue at www.twitter.com/postcardese.
Brace yourself for the message to Miss Gertrud. It is Super Fiendish and I'm afraid I have no answers. The mystery box it seems remains firmly sealed. Any ideas?