The only type person who would pick up on this Google logo change would be a mac user who loves Google. No, I am not talking about myself, I can't even see it with my own eyes, but designers who love Google.
Do you see it? Go to Google.com and let me know if you see the logo's background not being exactly the same shade of white as the rest of the page?
I couldn't tell, so I used a color picker tool and it is indeed slightly off white.
Here is a screenshot of me selecting the non-logo white:
Here is a screenshot of me selecting the white part in the middle of the G of the logo:
See how the HTML color is slightly off, proving maybe it is a different white?
This is no big deal but I love picking up on these crazy little changes at Google.