As marketers scramble to ride the latest technology, outdoor advertising (including billboards, transit shelters and buses, among others) is quietly becoming perhaps the last truly effective mass medium. One national company recently tried an experiment. As they launched a new addition to their product line, they confined their advertising in some markets to outdoor media alone. The result? The markets where outdoor advertising was the sole vehicle saw a 700% jump in sales. (That’s not a typo.) While targeted marketing requires a much more finely tuned approach, outdoor may be the last, best – and most cost-effective – way to reach all of the consumers in a market.