I just read about a new start-up that is scraping information from multiple sources to calculate how likely you are to leave your current job and selling this information to employers. What's concerning to me is that Stack Overflow is mentioned as a source of data by name in the article:
or use some niche industry sites, such as Stack Overflow, that combine aspects of social media and job boards
From what I can gather this app assigns you a "J-Score", which is supposed to indicate how likely it is that you're willing to leave your current job.
Emerging from that, if the app chooses to classify any particular activity on SO to increase your likelihood of leaving, this could have devastating negative effects on SO users. Companies might purchase that information and make layoff decisions based on it. If SE cannot prevent the data from being aggregated that way, this essentially means that activity on SE could lead to people losing their jobs - through no fault of their own. This could be an active incentive to stop using SE sites altogether for employees of unreasonable employers.
Also, looking further into this, it seems like they are purchasing per-person information about what links you click through. Facebook is able to directly track this via cookies and embedded facebook share buttons. Does SE have those in such a way that allows that? If so, do we need to reconsider having those?
I strongly believe SE needs to endeavour to nip this kind of activity in the bud in order to prevent a chilling effect on site activity.