Update January 2021: The tool mentioned in this article is no longer available. However, you can accomplish the same goal of making a transcript of YouTube videos by following the directions I've outlined in this video.
SnackVids is a new service that will generate a searchable transcript for any YouTube video of your choosing. To use the service simply copy the URL of a video, paste it into SnackVids, and then let SnackVids generate a transcript. When the transcript is completed it is displayed directly below the video. You can search the transcript for any keyword of your choosing. The keyword will be highlighted on the transcript. Click on the keyword highlighted in the transcript to jump to the corresponding section of the video.
Applications for Education
SnackVids could be a good tool to use when you come across a long tutorial video and want to see if the video will cover a topic or keyword that you're interested in. It's also convenient for jumping directly to specific sections within a video.
As with any automatic transcription tools, the quality of the transcript is dependent on the quality of the audio and the clarity of the narrator.