The speaker can monitor the ongoing reactions of a live audience, responding to the array of nonverbal signals by adjusting pace and content. Boredom, puzzlement, surprise, distraction, and close interest are not visible on the reader's face while you are writing. While you speak, however, all of them can be observed from moment to moment, and such reactions can be useful information. Responding in appropriate ways not only increases the effectiveness of communication but also ties speaker and audience together in a mutual enterprise that is impossible to achieve through the written page.