The problem is not what the site owner is able to see, but what Google sees. And it collects information about every site you visit, every article you read. It has access to all other information, like your browser fingerprint, etc. It does this even without being a Google customer - If you are, it get's worse - It can correlate it with every mail you get, every term you search, every step you take. This is a fundamental problem, and the magnitude is incredibly scary.