A LARGE OUTDOOR ADVERTISING SIGN HAVING A SUPPORT SURFACE AND A LONG, ADVERTISING MESSAGE STRIP ARRANGED IN CONTACT WITH THE SURFACE, EXTENDING AROUND OPPOSITE EDGES OF THE SURFACE AND THE WOUND UPON POWERED ROLLS AT THE REAR OF THE SURFACE, SO THAT THE STRIP IS FIRST WOUND AROUND ONE ROLL TO MOVE ALONG THE SURFACE IN ONE DIRECTION AND THEN REVERSELY IN THE OPPOSITE DIRECTION. ONE ROLL IS REMOVABLE FOR REPLACING THE ADVERTISING STRIP, THE OTHER IS NORMALLY NON-REMOVABLE AND HAS A LEAD STRIP FASTENED THERETO FOR EXTENDING AROUND THE SURFACE TO THE OTHER STRIP WHERE IT MAY BE RELEASABLY JOINED TO THE ADVERTISING STRIP BY A CONVENTIONAL ZIPPER. MEANS IS PROVIDED FOR HOLDING THE STRIP UPON THE SURFACE AGAINST WIND PRESSURES.