Google Search Logo has changed to look more simpler and flattened.
Now New, Then Old, Screenshot below.
The old Google logo had drop shadows that looks more appealing and interesting.
However, the new logo is flattened. Making it the same as new Yahoo logo.
And the top menu which was black has even simplified to a cleaner and whiter look, with Google+, Gmail and Images placed on the right side, instead.
It looks much interesting this way and users can be visually more focus to click Google+ and social online.
SIMPLICITY makes the world go round.