>How is this different from the information you give when you reserve the
>flight on the Web now, except for the date of birth?
Currently, any information you provide to an airline is NOT automatically shared with other commercial entities or government agencies and compared against other commercial databases. This type of data aggregation allows for the formation of a comprehensive profile on travelers, that may later be shared amongst government agencies and private firms. With this type of data aggregation, the government may not only know when you traveled and where, they may also know all of the items (i.e. books) that you purchased on your credit card and what items you bought at the grocery store, via your loyalty card. Once this door is opened, I'm not quite sure how it gets closed.
Steven