Google is re-working its search engine with a work-in-progress called Caffeine.

You can preview it here.

Notice, the preview does not have any AdWords ads, which would surely be included in a launch version. 

In my quick tests of Caffeine, the results weren't much different, with LinkedIn pages appearing higher than normal. Other than that, most rankings were changed very little (1 spot), if at all.

Tip of the Hat for the Notice: LifeHacker , Techtree