tedster - 5:41 am on Oct 5, 2012 (gmt 0)
It's not exactly a redesign. The page's appearance an be exactly the same.
Instead, it's additional mark-up within your existing source code so the various elements of your page communicate more detailed semantic information that search engines can use - and who knows what else in the future if they really catch on.
Here are some of the many threads on WebmasterWorld about it:
Shouldn't We All Be Developing Sites For Responsive Design [webmasterworld.com]
Developing Responsive Designs With Opera Mobile Emulator [webmasterworld.com]