This post discusses an aspect of privacy, which is is an important part of trustworthy computing on the web: “third-party content”. Most people browse the web, they think what they see in the address bar and the site they are visiting are the same thing. However, web sites today typically incorporate content from many different web sites.
For the sake of clear terminology, the site the user browses to directly (seen in the address bar) is the first-party site; the other sites that the first-party site incorporates in its site experience (but that the user hasn’t navigated to directly) are third-party sites.
When you browse to a first-party site, you know that it can collect information about how you use the site. What many users don’t realize is that technically, third-party sites can collect information about users as well. Users aren’t typically well-informed about which third-party sites are collecting what information, how the sites use this information today, or how the sites could use the information in the future.