Crowdsourced annotations data offers cognitive computing systems insights in lay semantics. This is especially important in health care, where medical terminology is often not aligned with patients `lay' language. However, the general crowd often has limited medical knowledge. Therefore this research investigated the opportunities of social health websites for obtaining ground truth annotations data for cognitive computing systems including clinical decision support systems. By identifying these websites and analyzing their data, it offers a starting point for the future utilization of user-generated health content for cognitive systems. However, the opportunities of social health data are currently limited by various legal regulations. Therefore this paper also dwells on the legal aspects of implementing social health data for cognitive computing systems.