Youtube has updated to a new design of UI, along with other products of google like: adsense, analytics, webmaster tools, gmail.
The most significant change is the background, it’s no longer white, replaced with a texture based background image, seems more visual appealing.
Besides color change, it has also changed the index page design, it’s 3 column design now, and the video list is displayed vertically one after another, instead of pile the video from left to right, and have the category list on the left column.
When click on the category tab, it loads the list by ajax, but the url in the address bar doesn’t change, it makes you can’t track the action by url in this part. And only a few videos in the category get displayed. So the only purpose is as a quick view of the content in the category, for the deep in video search, you still need to go for the Browse button on the top bar, or do some Search, that makes you able to dig deep inside the huge base of youtube videos.
So the index is mainly focus on casual video experience. If you already have something to look for in you, you will go for google search, youtube’s own search or specialized built in youtube browse feature.
I think the whole idea should be let user find what they want to find easily, efficiently. This is also the golden rule that the technology is heading. With so many videos in youtube, it’s already been a great role in internet, all kind of music, cultures mix. Besides the knowlege in printed books, online video is becoming another solid way for sharing knowledge: knowledge in sound,light form compensate in the text form.