The third-party tracking ecosystem continuously evolves in scope, therefore, understanding of it is at best elusive. In this thesis, we investigate this complex ecosystem from three dimen-sions. Firstly, we examine third-party trackers from a geographical perspective. We observe a non-uniform presence of local third-party trackers between regions and countries within re-gions, with some trackers focusing on specific regions and countries. Secondly, we focus on how trackers share user-specific identifiers (IDs). We identify user-specific IDs that we suspect are used to track users. We find a significant amount of ID-sharing practices across different organ-isations providing various service categories. Our observations reveal that ID-sharing happens at a large scale regardless of the user profile size and profile condition such as logged-in and logged-out. Finally, we quantify the effect of tracker-blockers, a popular option for the users to protect their privacy, on the page-load performance. The effect of such tools on the over-all user browsing experience is questionable as the blockage of trackers can disrupt the general website loading process. The tracker-blockers we studied have a considerable negative effect on page-load performance. Unexpectedly, we find that even highly popular websites are negatively affected. This thesis points to significant gaps in our knowledge about the inner workings of this complex ecosystem. Moreover, it highlights some of the challenges that we face when attempting to preserve user's privacy by using tracker-blockers.

This thesis project presents a research through design process, that has aimed to investigate and challenge internet users’ perception and awareness around the theme of online privacy and third-party trackers. This has been done by designing a critical design artifact called PrivacyLamp which takes form as a classic lamp, that through a secondary (dis)functionality is designed to work as an mediation of potential third-par- ty-trackers activity on the user’s local network. PrivacyLamp has been developed through an iterative design process, guid- ed by relevant literature and works within the eld of critical design, physical data visualization, and design for re ection, which all have worked as a foundation for the design of such an artefact. The prototype has been evaluated together with six participants, who all adopted the prototype into their domestic settings to experience it as a part of their everyday life for a few days. The aim of this qualitative study has been to investigate how a defamiliarized domestic object can work as an ambient display to question the invisible ow of connec- tivity and its complication within online privacy, as well as the narratives and experiences users develops in relation to this.