Abstract-Today, third-party tracking services and passive traffic monitoring are extensively used to gather knowledge about users' internet activities and interests. Such tracking has significant privacy implications for the end users. This paper presents an overview of the third-party tracking usage. Using measurements, we highlight the current state of the third-party tracking landscape and differences observed across tracking service classes (e.g., advertising, analytics, and content), across domain categories (e.g., popular vs. less popular, and national vs. global domains), and with regards to the organizations that owns many of the tracker services, when using HTTP and HTTPS, respectively. Understanding these differences help answer questions related to the third-party services that track modern web users and their coverage of our browsing.