Amit Banerjee pinged me about a Google experiment he noticed over the weekend. He calls it a sticky top bar, where the top Google bar sticks to the top, even when you scroll.
Here is a static picture, also notice the new look for Google Instant Previews.

He even posted a screen cast of it in action:
Pretty interesting, don't you think?
So far, early feedback on this is positive. A "sticky" or "permanent" top bar is not a new concept, but would it be bad for Google to use?
Forum discussion at WebmasterWorld.

Comments:
Treb
07/18/2011 06:20 pm
Great videos... Thanks for sharing the post...
Pet Assure
07/18/2011 08:25 pm
The discussion at Webmaster World you linked to is talking about infinite scrolling, not the absolutely positioned top bar.
SEO Positive
07/18/2011 09:37 pm
i personally think its much better, it also enables you to re-search quicker when needed too.
Peter
07/25/2011 08:36 am
But if you scroll down through the results with the Page Down key, the result that was just hidden below jumps up to become just hidden by the scroll bar, so you never see it (or not enough to notice it)