Miguel Helft at the New York Times has a good article this morning, "YouTube's Quest to Suggest More", on how YouTube is trying "to give its users what they want, even even when the users aren't quite sure what that is."
The article focuses on YouTube's "plans to rely more heavily on personalization and ties between users to refine recommendations" and "suggesting videos that users may want to watch based on what they have watched before, or on what others with similar tastes have enjoyed."
What is striking about this is how little this has to do with search. As described in the article, what YouTube needs to do is entertain people who are bored but do not entirely know what they want. YouTube wants to get from users spending "15 minutes a day on the site" closer to the "five hours in front of the television." This is entertainment, not search. Passive discovery, playlists of content, deep classification hierarchies, well maintained catalogs, and recommendations of what to watch next will play a part; keyword search likely will play a lesser role.
And it gets back to the question of how different of a problem Google is taking on with YouTube. Google is about search, keyword advertising, and finding content other people own. YouTube is about entertainment, discovery, content advertising, and cataloging and managing content they control. While Google certainly has the talent to succeed in new areas, it seems they are only now realizing how different YouTube is.
If you are interested in more on this, please see my Oct 2006 post, "YouTube is not Googly". Also, for a little on the technical challenges behind YouTube recommendations and managing a video catalog, please see my earlier posts "Video recommendations on YouTube" and "YouTube cries out for item authority".