The official Release Notes for the new site features is available on
the blog, here:
http://www.youtube.com/blog?entry=Lsn9BnVuSAM

Here's the summary what's new on YouTube...

* New Options for Uploaders
* HD Browsing Goes Global
* AudioSwap Adds Recommendations
* Subscription Tab in More Places
* Subscription Suggestions
* Username Alternatives
* A Tooltip to Help With Precise Seeking

Take a look @ the blog for more info! As always, we love hearing your
feedback on new releases... so comment under the blog post (http://
www.youtube.com/blog?entry=Lsn9BnVuSAM)

or

let us know your thoughts by responding to this post.

Hope this info's useful! And as always, we appreciate you visiting the
Community Help Forums ;)