According to Search Engine Roundtable:
A new thread at Search Engine Watch Forums named “The Video Void” has continued discussion. There is a lot of skepticism on if these video ads will work or not. AdWordsRep noted that he/she just passed “the URL for this thread on to the Video Ads folks.” AdWordsRep continues, “here is your chance to have your opinions/comments/irritations/suggestions regarding Video Ads heard by exactly the right folks.”
As you may recall, Google AdWords advertisers have the option of creating and running video ads through the Google AdWords program. However, keep in mind that this really isn’t true Context Video.
True contextual video is really when an application “listens” to a video and figures out what the video is about and then displays an ad based on the content of the video. Google video ads run based on the content of the web page where that video ad would appear.
Right now Google’s system can spider a web page and figure out what “that web page is about”, and we call that contextual advertising. Google’s system is not sophisticated enough (yet) to figure out what a video is about. Hopefully they’ll get there soon or purchase the technology and incorporate it into their system.