What Are Fiber Art Postcards?
"They are small pieces of quilted art. Some are fairly stiff, while others are flexible. They must be no larger than 4" x 6" and no thicker than 1/8" in order to be mailed. The postage must be hand cancelled, and they require a first class stamp instead of the regular postcard rate." Information is from http://www.art2mail.com/faq.php - a resource about FAQ's for fiber art postcards.
Fiber art postcards have also been used successfully for fundraising by Fiberart For A Cause for the American Cancer Society - http://www.virginiaspiegel.com/NewFiles/ACSFundraiser.html