Abstract: A data distribution system includes a server computer for transmitting email files to a computer network for access by remote computers having email client computer software for displaying the email files; the server includes a script program as a portion of a secondary e-mail message that also includes tracking information; a predefined message is also stored as a main message, the script program also including a command that displays the predefined message by retrieving the second source file. The Script program can further include a command for passing information to the server computer, and a command for replacing a first image with a second image. When the server computer receives the transmitted information, a reply is transmitted, and the script program executes the command for replacing in response to the reply. The command for passing the information can be executed in response to a user action directed to the first image.