True. I think a big danger underlying people's general reservations about this stuff is government abuse of all this newly available data.
Corporate abuse too. If someone is out-spoken against Google, what's to stop Google from silencing them by threatening to reveal secret information about them (or to plant information about them, like child porn searches in their search history).
Not only that, but it makes it easier for 3rd party groups to try and gain information to silence opponents, Scientology being the first to come to mind.
In general, all of this information will benefit people, but possibly only people that 'keep their head down' and don't 'go against the flow.' For people that have strongly held beliefs that are against the 'norm,' it will make it easier for them to be attacked and (eventually) silenced. It will be the tool used to bludgeon people into becoming a homogenized society.
No amount of posturing and rhetoric about rights and privacy will long delay the world we're moving into; those are political activities, and the coming abolition of privacy is a technological and economic matter; politics can only weakly affect such things without becoming overwhelmingly invasive -- a solution more to be feared than the problem.