I'll bet that caught your attention, huh? Actually, it just refers to mailing art without an envelope - such as in the case of these postcards I made:
The theme for this Paper Traders swap was one "zetti" postcard and one "steampunk" postcard. I'm not sure I quite captured the themes in their true intent but I'm not unhappy with the results. A big thanks to Lorna for hosting this one - it was fun!