Closed captions allow you to transcribe the audio portion of your e-show and display the text on the screen while the e-show is playing. The location of the onscreen text depends upon the layout template you chose.
Adding closed captioning makes the media of your e-show accessible to users who are hard-of-hearing and to those watching it without audio. For example, someone could watch your e-show without audio if they were in a crowded room where they didn't want to disturb others or if their computer was not equipped with a sound card.
You can add closed captioning to your e-show using the Closed Caption tab of the Media Properties dialog box to transcribe the audio portion by hand.