See these articles:
Netflix Contest Seen As Posing Privacy Risk
Netflix is about to commit a privacy Valdez with its customers' viewing data
AOL, Netflix and the end of open access to research data
Once again Netflix plans to violate the privacy of those who rate the movies they rent. Two University of Texas computer scientists demonstrated that the Netflix database of 500,000 with movie ratings could be re-identified, revealing sensitive political and sexual preferences of the actual people who rated movies. Netflix did not get the consent of renters to expose their ratings to the public or ot researchers.
Yet Netflix is moving ahead to release even MORE personal data for its next million-dollar contest. The major media (NYT's STeve Lohr for example) has NOT reported at all on how Netflix is violating movie renters' privacy, but instead trumpets the prizes paid to those who develop more accurate ways to predict which movies you will want to watch next.
The problem of re-identification is VERY serious for the healthcare system because health data is impossible to de-identify. It is so rich in detail that de-identification is almost impossible.
Today, the treasure trove of all Americans' sensitive health data is being endlessly used and disclosed without informed consent to millions of "covered entities" and "business associates" (and their millions of employees)--subjecting EVERY American to the theft, sale, and misuse of the most sensitive personal information that exists.
Who will hire you knowing all about your prescriptions, illnesses and genes?