If I'm reading that right, it means they can, legally, monitor and publish anything you do with the browser. Visit a porn site? Google know about it. Download music? Google know about it. Try to find out how to build a bomb? Google know about it.
I can just see The Sun headline now, "BRAD PITT USES CHROME TO SEARCH FOR GERMAN MIDGET PORN!"
Now, I doubt they particularly care, but it is a bit Big Brother, isn't it? (I'm aware I am usually the last person to think about personal freedoms)