Don't know how many users are aware that Google Video actually provides a 'start playing at search term' function for videos with transcript. This feature should have come with the pin point feature in comments where users commenting on a specific section of a video can put the start time in the h:mm:ss or m:ss format, and Google will automatically hyperlink to those times in the video. This is how the description in the Help Center:
If a search term you enter appears within a video's transcript, you can start playing the video from that term's location in the video. For example, from the search page for the "Similan Islands", you can see that the video titled "Scuba Diving in Thailand and Burma" has a link that says, "Start playing at search term (0:31)." Click on this link to be instantly linked to the clip containing your search term.Here is an exmaple if you search for Google:
If Google could go further by introducing a voice recognition program which can automatically translates the speech in videos into searchable text. Though there is no perfect program on earth that can transcript speech into text with 100% accuracy, it would, at least be more useful if users can search for exact content in the video rather than just the description and tags given by users. I am pretty sure Google is working on this (or is finding a company which is already good at this).