A system and method for narrowcasting text messages to a plurality of cellular phones. The system and method allow a potential user to opt in to receive the text messages the user wants to receive. The potential user can opt in through a computer network based web page. Once the potential user sends a sign up request application to participate via the computer network, the user will receive a first text message containing an authorization code on their cell phone. The user enters the authorization code into the web page and sends the authorization code. Receipt of the authorization code back through the computer network will trigger the phone number of the potential user to be added to a list of authorized text message receivers. A narrowcaster then instructs the central computer to narrowcast text messages to the phone numbers on the list that have indicated they want to receive messages on a certain topic.