Bus mailing refers to the practice of distributing promotional or informational materials, such as flyers, brochures, or coupons, to a targeted audience by placing them on or inside public transportation vehicles, such as buses or trains. This method of marketing allows businesses to reach a large and diverse audience, as well as to specifically target certain demographics based on the location and route of the bus. Bus mailing is a cost-effective and efficient way to advertise products or services, and can be a valuable tool for businesses looking to increase brand awareness and attract new customers.