Along with the changes Google have been making in social networking with Google+, they have also been updating all their other services in the process to coincide with the new look.
Users are now greeted with a black bar across the top of their sites with a +You in the top left hand corner, giving the impression of a more personal experience. And this personalisation is carried through to your search results if you are signed in. For example, starred results appear at the top of your search results and websites that your friends have shared on social networks now seem to be more prominent. Google allows you to see who has shared these websites also.
In terms of design, Google have gone for a nice matte finish, subtle icons and dashes of colour to highlight the call to actions. The red and blue of the Google logo appear to be the most prominent, which makes for a nice contrast.
Google and the web are becoming more synonymous by the day.