YouTube added a major feature this past year with the addition of closed captioning. They now close caption all videos using voice recognition technology as they are being uploaded and add the text to a CC file. Video CC text can also be updated and corrected. On older videos you can go into your account and hit the transcription button to have your video closed captioned. Closed captioning works unless Google can’t figure out what is going on, including videos with music in them if the words are clear enough. This is pretty amazing and often pretty accurate.
Closed Captioning is important not only for hearing and site impaired folks, but for search. Google and YouTube index this copy for their search results. Why do we use this? Most videos are watched for no more than 20 seconds before the viewer leaves. We want to get our essential message or key phrase into those first few seconds. Because someone has come here through a search, we want to make sure they hear or see those key words right away. We want to reward our viewers with a positive search experience based on the key words that we gave them. If we are lucky maybe they will stick around and watch the entire video.