Radio has a vast appeal and it is available nearly everywhere -- work, car, home, shopping. One could almost state that radio is the background soundtrack to our lives. We listen to radio, but we do not always hear what is being said, what message is being delivered. Still, radio is very effective in delivering messages. Radio news is almost instantaneous. Even with the advancement of 24 hour news channels, radio is a first line for information in part because that information is available anywhere. This is added with the advancement of apps such as I heart radio. Radio is also local (even though apps allow one to listen to radio from other markets, generally individuals will stick stick with the local stations when looking for information, or that person may keep up to date with a favorite Detroit radio station). The local nature of radio insists on it focusing on relevant local content, making it a key for local information. Radio also transcends socio-economic groups (world wide which is why it is used for AIDS awareness and health awareness in many third world countries) so that it is able to reach individuals that may not be reached through mediums such as cable or the Internet.
As far as advertising goes, radio is cost-effective and considerable studies show it increases consumer affinity, recognition, and is able to target a very specific audience. The audience specificity could be its greatest strength. Television and magazine advertisers must consider a wider age gender socioeconomic status when advertising, whereas radio can practically pinpoint its listenership.