http://folyo.me/guides/quora-redesign
For what it's worth, here's what Quora's own head designer had to say about it:
"You're right about a few problems you decided to solve, wrong about all the proposed solutions."
(http://twitter.com/#!/artypapers/status/131401350272647168)
In a number of areas like "Answer question" and the search bar, I felt you helped give them more prominence which is good!
I'm a sucker for less is more and many of the tweaks you made to remove clutter also helped.
That said I found your method of notification and menu aggregation a little to heavy handed.
On a side note: When doing a site redesign like this, it is a good idea to try and keep the same content as your sample. Adding that new copy forces the viewer to separate what is a design change from what is content. This in turn causes people to loose focus on the design changes, and even in some cases fail to see or understand those changes.