Narrowcasting1 – communicating with small groups of people who have an interest in you.
Broadcasting1 – communicating with huge groups of people in hopes that a few will be interested in you.
Broadcasting used to be the only way you could get your word out. Even if you had a one shop business in a small town, you had to broadcast via your local newspaper, radio or tv in hopes that your message would reach the few that have a need for your services. Over a century of broadcast design has evolved effective design practices for broadcasting.