Because the “Host” for both requests is identical (www.cdc.gov), the user is only interacting with a single party and such requests are called “first-party requests.” The only two parties who know the user is looking up information about HIV are the user and the CDC. However, the HTML file also contains code that makes requests to outside parties. These types of third-party requests typically download third-party elements such as images and JavaScript. Due to the fact that users are often unaware of such requests, they form the basis of the so-called