The implications for research ethics, though, are greeter. I do think this is just one more example of how we CANNOT promise research participants confidentiality, privacy, or anonymity. Any data set rich enough to be useful for research will (almost) always be rich enough to allow some of the people in it to be re-identified – through the demographic information on them, the phenotypic/health information on them, or the genetic information on them. Real anonymity in research collection is an occasional, and decreasingly common, event.

I worry that people who agree to be research subjects don’t really know this (investigators certainly don’t go out of their way to make sure the possible participants understand it!). They aren’t likely to be harmed – but if they are harmed (or even learn that their identity was compromised without harm to them), their anger will be all the greater for the fact that they didn’t really understand what they were getting into.