Privacy Implications of Health Information Seeking on the Web
  This article investigates privacy risks to those visiting health- related web pages. The population of pages analyzed is derived from the 50 top search results for 1,986 common diseases. This yielded a total population of 80,124 unique pages which were analyzed for the presence of third-party HTTP requests. 91% of pages were found to make requests to third parties. Investigation of URIs revealed that 70% of HTTP Referer strings contained information exposing specific conditions, treatments, and diseases. This presents a risk to users in the form of personal identification and blind discrimination. An examination of extant government and corporate policies reveals that users are insufficiently protected from such risks. 
Tim Libert
cs.CY cs.CR