The debate has been going for long; now Matt Cutts in his blog has released some interesting screenshots where senseless words like ’ mbzrxpgjys’ yield similar results in Bing and Google. Along with it is accompanied a 40 minute video giving you more details.

Initially it was posted in Google webmaster blog now being posted by matt cuts the debate turns even intense.
Google claims that they just manipulated results for certain irrelevant words and would find the same results two weeks later on Bing and also Google says Microsoft does take advantage of IE users to get their private data like browsing history to give suggested sites. On the other hand Bing denies it saying they just using click through data to manipulate the results and accuse Google of tracking private data from millions of users
using Google toolbar. So the blame game goes on

If you want to dive into this topic even deeper, you can watch the full forty minute video

http://www.mattcutts.com/blog/google-bing/

With Microsoft denying the claims and Google proving it, one can say you cannot hide anything from Google search