THE MEANS for companies to communicate with customers expand on an almost daily basis. The Internet, cell phones, movie theaters, kiosks and dozens of other outlets have joined print, radio and TV as popular methods of delivering ads and messages. The market research firm Yankelovich quantifies the impact of the growing array of communication methods this way: consumers encounter between 3,500 and 5,000 marketing messages a day, or three to four times as many as in the 1970s. In this environment, conventional wisdom would suggest that no single medium would prevail…and certainly not the one that has been around the longest. In fact,