Simply put a number of businesses share space on a 9 X 12 Postcard with each having an ad to promote their business. Most will craft an offer for a specific deal with a coupon to be redeemed by the recipient. Commonly, neighborhoods of single family homes in a range of 5,000 to 10,000 are selected for mailing. It is cost efficient for most businesses where going alone would be out of the price range for most local businesses.