This is a long shot, but I'm going to give it a try anyway.
I remember reading not too long ago (within the past couple of months) about researchers who studied the ability of a person's social network to diagnose or detect that person's disease. The gist of the study was that the network did surprisingly well.
I don't remember the exact study design (whether network members were explicitly asked to guess, or whether the researchers harnessed guesses from off-hand comments). I don't remember how the user's social network was defined either (but presumably it was probably through Facebook or Twitter). In fact, I don't remember much beyond what I've written above, and I even might have remembered something incorrectly. I only read the headline and skimmed the article. However, I realize the details of this article are now incredibly important to me for a grant proposal.
As soon as the system allows me to, I will offer a bounty of 200 points. Help please!
NOTE: I am not thinking of this study, as compelling as it is. I recall the study I'm looking for being more of a scientific study rather than an anecdotal case report.
Not enough for an answer, but might help as a starting point: http://www.ted.com/talks/nicholas_christakis_how_social_networks_predict_epidemics.html
maybe not enough for an answer, but enough for a +1...