It is almost impossible to visit a website today that does not have tracking tools implemented. Either for the purpose of analytics or for advertising, data is being collected about us on virtually every website. This thesis studies how online tracking works – which methods that are being used, how they work and what kinds of data is actually being collected about us. To address these methods first hand, an experimental website is built, where the tracking tools that are most frequent on the largest Norwegian websites today are implemented. We also study what kinds of data we are able to collect from our experimental website, and we also study how large companies such as Google track us around the Web. The results indicated that privacy on the Web does not exist in 2020. For the average Web user, all actions they make are tracked and monitored on virtually every single website they visit. Large American corporations such as Google and Facebook are present on nearly all the largest websites in the world, and collect vast amounts of data – data which is then aggregated in a way which can predict our behavior even better than ourselves. Any person who browses the Web without anti-tracking and ad- blocking software in their browser, such as AdBlock or Ghostery, is completely exposed to sophisticated surveillance on almost every website they visit. The underlying motivation for this surveillance is advertising profits, and the large players in today’s market have large and obvious financial interests in circumventing and stopping anti-tracking efforts.