In the years I have learned that tiny changes on the interface - sometimes just a few pixels more space or a brighter color can have big impacts on conversion rates.
The biggest change I have seen for me by "little changes" was moving the "Buy now" button 15 pixels and getting a better conversion right after it.
Now Google is rolling out the Jazz thing:
But nobody started to guess around on the impact?
a) toolbar fixed on the left of the results - MUST have an impact!
b) more style sheet entries to make the interface look fancy... would guess that sums up to a few more terabytes of traffic daily, when called by a few hundred million people?
c) the links are in a brighter blue, no underline - I personally have less clicks on brighter colors!