You're perhaps right. Of course, these people are on things like Facebook, Twitter and blogs and if you can narrow down age, gender, location and medical condit

You're perhaps right. Of course, these people are on things like Facebook, Twitter and blogs and if you can narrow down age, gender, location and medical condition, you might be able to correlate with public posts. You can also look for specific people in there if you have certain kinds of prior information about them: For example, Aravind Narayanan was able to de-anonymize some part of the Netflix set [http://arxiv.org/abs/cs/0610105 http://arxiv.org/abs/cs/0610105]. Maybe that won't translate to this data.