Demystifying Content-blockers: A Large-scale Study of Actual Performance Gains

With the evolution of the online advertisement and tracking ecosystem, content-filtering has become the reference tool for improving the security, privacy and browsing experience when surfing the Internet. It is also commonly believed that using content-blockers to stop unsolicited content decreases the time needed for loading websites. In this work, we perform a large-scale study with the 100K most popular websites on the actual performance improvements of using content-blockers. We focus our study on two relevant metrics for measuring the browsing performance; page size and loading time. Our results show that using such tools results in small improvements in terms of page size but, contrary to popular belief, it has a negligible impact in terms of loading time. We also find that, in the case of small and lightweight websites, the use of content-blockers can even result in increased loading times.