This is the reason why we have the Data Protection Act in the UK.
Unfortunately it is in the US Government's interest to encourage this kind of thing because it allows them to practically simulate the opinions of their greater population and that gives them more control. Fortunately here in the UK we run our own government, and that body understands that this kind of thing can remove an individuals right to privacy.
The only problem with the Data Protection Act is that organisations are obligated to actively dispose of un-useful information. So if say I was to phone one of my old schools and ask about my attendance they wouldn't be able to tell me because the Data Protection Act forces them to dispose of any information that is not necessary for them to record.
The government is now allowing specific bodies like the Department Of Education to archive this data, but future historians will curse the Act for everything its worth, because great records like the Domesday Book provide an important view into our past. Just like the ability to look back over a hundred years of weather data allows us to predict our climate, to see the effects of Global Warming, but even more importantly allows us to discover hidden problems like Global Dimming. So can other archived data be useful in other ways.