Support Media Advertising means the advertising media used to reinforce messages sent to receivers/ audience/markets through other more effective and dominant and more traditional media.
Usually outdoor advertising is called support media advertising. There are different medium used for advertising in which outdoor advertising is important. Billboards, transit ads, promotional products, sky advertising, yellow pages advertisement, advertising used in movie theaters, advertising in trains etc. are the example of support media advertising. It lets any company to gain awareness and exposure.