The phrase "reach of one's message" refers to the extent or limit of how far a message can be spread, delivered or disseminated to an audience. It is the potential impact or influence that a message can have on people, depending on the effectiveness of its communication and distribution. The reach can be measured by the number of people who are exposed to or receive the message, and it can be influenced by factors such as the medium used, the target audience and the content of the message.