And really, why should we trust Facebook and third-party app developers to respect users' privacy when their business model depends on doing the opposite? Facebook clearly recognizes the enhanced value of its user data when combined with medical data. That should tell lawmakers that the definition of "protected health information" needs an update. If we can still think of big data as something that could be harnessed for social benefit, we need to create regulations that allow users to consent to participate, like they do in clinical trials. We don't need to lock down all the data; we just need to distribute the power to access and share it so patients and future patients receive benefits, rather than harms, from sharing their experiences online.