TIME to revisit the always compelling  and often disconcerting  debate over digital privacy. So, what might your movie picks and your medical records have in common?

How about a potentially false sense of control over who can see your user history?

While Netflix and some health care concerns say they have been able to offer study data to researchers stripped of specific personal details like your name, phone number and e-mail address, in some cases researchers may be able to re-identify you by correlating anonymous information with the digital trail that you’ve left on blogs, chat rooms and Twitter.

Of course, you may be fine with that. On the other hand, you may not want complete strangers rummaging around in your history of movie selections or medical needs.

For example, contestants in Netflix’s competition to improve its recommendation software received a training data set containing the movie preferences of more than 480,000 customers who had, as they say in the trade, been “de-identified.” But as part of a privacy experiment, a pair of computer scientists at the University of Texas at Austin decided to see if it was possible to re-identify those unnamed movie fans.