A novel method at least includes: receiving at least one placement offer for the placement of an advertisement, the offer including proposed consideration; accepting an placement order; and displaying an advertisement which is the subject of an accepted placement order on a plurality of mobile, changeable advertising message displays carried by a plurality of coordinated automobiles, which changeable displays are capable of displaying more than one separate message at different times. Each changeable message display at least includes: a visual display; a multiple advertising message generator coupled to the visual display, the multiple message generator adapted to generate a plurality of different messages; and an message selector adapted to select a current message to be displayed.